Patent Publication Number: US-2020284707-A1

Title: Environmental Conditioning Mechanical Test System

Description:
CLAIM OF PRIORITY 
     This patent application claims the benefit of priority of U.S. Provisional Patent Application Ser. No. 62/585,516, filed Nov. 13, 2017 (Attorney Docket No. 3110.019PRV), which is hereby incorporated by reference herein in its entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     This invention was made with government support under DE-SC0013218 awarded by the U.S. Department of Energy. The government has certain rights in the invention. 
     COPYRIGHT NOTICE 
     A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to the software and data as described below and in the drawings that form a part of this document: Copyright Bruker Nano, Inc.; Goleta, Calif. All Rights Reserved. 
     BACKGROUND 
     Materials (e.g., metals, polymers, composites, or the like) include a plurality of mechanical and electromechanical properties (e.g., Young&#39;s Modulus, hardness, ductility, resistance, capacitance, or the like). One or more instruments are used to test the mechanical and electromechanical properties of the materials. In some examples, the mechanical and electromechanical properties of the materials in an environment vary with the characteristics of the environment (e.g., temperature, humidity, or fluid composition). 
     SUMMARY 
     A mechanical testing instrument a probe having a probe tip) is included in a mechanical testing system, and the system tests the mechanical properties of a material sample by, for instance indenting, pulling, or scratching the sample. In some examples, the mechanical testing instrument is heated, for instance the mechanical instrument is heated to substantially equal a temperature of the sample of material. By heating the probe to a temperature equal to (e.g., including approaching) the temperature of the sample heat transfer between the sample and the mechanical testing instrument is minimized. Accordingly, upon engagement between the sample and the probe (e.g., by pulling, scratching, or indenting the sample of material) the precision and accuracy of the test performed by the mechanical testing instrument are improved. 
     The present inventors have recognized, among other things, that a problem to be solved can include altering the temperature of the mechanical testing instrument without affecting the mechanical or electromechanical properties of the mechanical testing instrument including the shape and size of the instrument or causing it to move (e.g., through expansion or contraction, thermomechanical drift or the like). Additionally, the present inventors have recognized, among other things, that a problem to be solved can include localizing heat transfer proximate to the mechanical testing instrument. Further, the present inventors have recognized, among other things, that a problem to be solved can include reducing the stress and strain applied to a heating element that is utilized to alter the temperature of the mechanical testing instrument. 
     The present subject matter can help provide a solution to this problem, such as by providing a heating element that is mechanically isolated from the mechanical testing instrument. For instance, and in some examples, a portion of the heating element is in close proximity to the mechanical testing instrument and surrounds the instrument to allow for heat transfer from multiple directions relative to the instrument while at the same time enclosing the instrument and minimizing escape of the transferred heat. Additionally, the heating element is separated from the mechanical testing instrument by a gap (e.g., a space, a distance, a void, a cavity, or the like). Positioning the heating element in close proximity to the mechanical testing instrument (e.g., the tip of the probe positioned at a distal end of the probe) localizes heat transfer to the mechanical testing instrument. Accordingly, heat transfer to other portions of mechanical testing system is minimized, and the effects of heating the other portions of the system are thereby reduced. 
     In contrast to heating the mechanical testing instrument with a mechanically isolated heating element, in other example a heating element is directly coupled to a proximal end of the mechanical testing instrument (e.g., a base of the probe). Heat generated by the heating element is conducted through the mechanical testing instrument toward the distal end of the mechanical testing instrument where the mechanical testing instrument engages with the sample. In some examples, because the heating element is directly coupled with the mechanical testing instrument, the heating of the mechanical testing instrument affects the mechanical response of the mechanical testing instrument (adds mass to the instrument). Alternatively, or in addition, the heating affects a transducer coupled with the instrument that measures displacement (and optionally drives) the mechanical testing instrument or a force applied to the mechanical testing instrument. Mechanically isolating the heating element from the mechanical testing instrument as described herein localizes the heating of the mechanical testing instrument to the probe (e.g., the component that will engage with the sample) while minimizing distributed heating of other portions of the instrument and the associated drawbacks. Accordingly, the precision and accuracy of the tests conducted by the mechanical testing system are enhanced. 
     Additionally, mechanically isolating the heating element from the mechanical testing instrument reduces stress and strain applied to a heating element. For instance, in some examples the heating element is directly coupled to the mechanical testing instrument, and the mechanical testing instrument is engaged with the sample to conduct a test of the mechanical or electromechanical properties. In one example, the mechanical testing system applies a force to the mechanical testing instrument (e.g., to indent the sample, pull the sample, or scratch the sample). Because the heating element is coupled to the mechanical testing instrument, such as a movable probe, the applied force is also applied to the heating element. In some examples, the application of force to the heating element reduces the lifespan or reliability of the heating element, and increases maintenance required for the heating element (e.g., replacement of the heating element). In other examples, the additional mass of the heating element decreases the mechanical performance (movement, fidelity of signal to specified movement or force, or the like) and sensitivity of the instrument. As described herein, by mechanically isolating the heating element from the mechanical testing instrument, the effect of the heating element mass on the mechanical testing instrument movement and sensing are minimized. Accordingly, one or more of performance, operational lifespan or reliability of both of the heating element and the mechanical testing instrument are enhanced. 
     This overview is intended to provide an overview of subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent application. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document. 
         FIG. 1  is an isometric cutaway view of one example of a multi-instrument assembly including a multiple degree of freedom sample stage. 
         FIG. 2  is a perspective view of a testing assembly that includes the multiple degree of freedom sample stage shown in  FIG. 1 . 
         FIG. 3  is a detailed perspective view of the testing assembly shown in  FIG. 2 . 
         FIG. 4  is a perspective view of one example of a heating jacket. 
         FIG. 5  is a side view of the heating jacket of  FIG. 4 . 
         FIG. 6  is a top view of the heating jacket of  FIG. 4  with a probe received in the heating jacket of  FIG. 4 . 
         FIG. 7  is a side view of a mechanical testing instrument. 
         FIG. 8  is a perspective view of the mechanical testing instrument of  FIG. 8 . 
         FIG. 9  shows one example of a method for testing the mechanical properties of a material. 
         FIG. 10  is a schematic view of a system for correcting thermomechanical drift in a mechanical testing assembly. 
         FIG. 11  is a schematic view of an interferometer system 
         FIG. 12  shows one example of a method for correcting thermomechanical drift with a mechanical testing assembly. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a partial cutaway view of an example multi-instrument assembly  100 . As shown, the multi-instrument assembly  100  includes an instrument chamber  102  surrounding a testing assembly  112  and a plurality of instruments (e.g., a microscope) including first, second, third, and fourth instruments  104 ,  106 ,  108 ,  110 . As shown, each of the first through fourth instruments  104 - 110  is clustered around an area adjacent to the testing assembly  112 . For instance, the first through fourth instruments  104 - 110  are arranged and include instrument axis and focal points or working distances (e.g., working regions) defining or within a localized coincidence region near the testing assembly  112 , for instance, adjacent to a multiple degree of freedom sample stage  116 . As will be described in further detail below, the assembly  100  includes a heater that alters the temperature of one or more components of the assembly  100 . Additionally, the assembly  100  includes one or more systems to isolate and compensate for thermomechanical drift in one or more components of the assembly  100 . For instance, the position of one or more components of the assembly  100  may vary relative to other components according to changes in temperature of the components (e.g., small-scale movements at the micrometer or nanometer level) Further, the multiple degree of freedom sample stage  116 , a component of the testing assembly  112 , is configured to orient a sample (e.g., the sample  300  shown in  FIG. 3 ) on a sample stage surface (e.g., the sample stage surface  208  shown in  FIGS. 2 and 3 ) into a plurality of orientations relative to two or more of the instruments of the first through fourth instruments  104 - 110 . 
     As shown in  FIG. 1 , the testing assembly  112  is positioned within the instrument chamber  102 , as previously described herein. As shown, the testing assembly  112  includes a mechanical testing instrument  114  such as an indenter, a scratch (laterally moving) mechanical testing instrument, tensile testing instrument or the like. The mechanical testing instrument  114  is configured to interact with a sample present on a sample surface stage of a sample stage, such as a multiple degree of freedom sample stage  116 . For instance, the multiple degree of freedom sample stage  116  is configured to position a sample of a material for interaction with the mechanical testing instrument  114  while at the same time allowing for observation and further manipulation by one or more of the first through fourth instruments,  104 - 110 . 
     In the example including the multi-instrument assembly  100 , the assembly includes one or more instruments. For example one such instrument is a microscope instrument such as a scanning electron microscope including, for instance, a first instrument  104  such as an electron gun and a second instrument  108  such as an electron back scatter detector. In another option, the multi-instrument assembly  100  includes a third instrument  110  such as a secondary electron back scatter detector and a fourth instrument  106  such as a focused ion beam gun. In one example, the fourth instrument  106  is a tool configured to further process the sample positioned on the sample stage surface. For instance, the fourth instrument  106 , in one example a focused ion beam gun, is configured to remove portions of the sample and expose previously unavailable portions of the sample for further study and interaction with the mechanical testing instrument  114  and one or more of the first through third instruments  104 - 108 . 
     The assembly optionally includes an environmental chamber  118  configured to control one or more environmental characteristics including, but not limited to, pressure, temperature, atmospheric composition, humidity or the like. The example sub-systems for the environmental conditioning system include, but are not limited to, a vacuum chamber (e.g., a pressure chamber configured for one or more of negative, ambient or high pressure testing), cryogenic cooling system, humidity system, atmospheric composition and high temperature systems. In an example system  100  including the environment chamber  118 , the chamber is included as part of the instrument enclosure (e.g., the enclosure is a pressure vessel), allowing pressure variations from 10-6 Torr to 1000 Torr. The transducer, probe, optical imaging system, and stage (including one or more degrees of freedom) fit within the pressure vessel (the instrument enclosure). 
     The other various environmental subsystems that control one or more other environmental characteristics, such as temperature and humidity, are optionally mounted to the stage (e.g., the sample stage  116 ) and fit within the pressure vessel. These systems are localized to a zone proximate to the sample and the probe. For instance, these systems are included in a housing that surrounds the sample and the probe and accordingly affect a smaller volume of space relative to the remainder of the instrument enclosure. This minimizes the energy input (e.g., for heating), approach time to reach specified environmental characteristic values, and system requirements, while also minimizing characteristics that may be adverse to measurement (such as drift) to enhance testing stability. 
       FIG. 2  shows one example of the testing assembly  112  previously shown in  FIG. 1 . As previously described, the testing assembly  112  includes a testing instrument, for instance a mechanical testing instrument  114 . The testing assembly  112  includes a stage configured to support and present a sample for testing with the instrument  114 . For instance, in the example shown in  FIG. 2 , the stage includes a multiple degree freedom sample stage  116 . 
     The testing assembly  112  includes a testing assembly platform  200  sized and shaped to receive and mount each of the mechanical testing instrument  114  and the stage, in this example, the multiple degree of freedom sample stage  116 . The testing assembly platform  200  further includes an assembly mount  202 . The assembly mount  202  in one example is configured for positioning with and engagement to a mounting stage  101  of the multi-instrument assembly  100  (see  FIG. 1 ). In a system including the instruments  104 - 110  the assembly mount  202  allows for the actuation of the testing assembly  112  relative to the instruments  104 - 110 . Further, the multiple degree of freedom sample stage  116  (when included) provides additional orientation and positioning ability for a sample positioned on the sample stage surface of the multiple degree of freedom sample stage  116 . 
     Referring again to  FIG. 2 , the multiple degree of freedom sample stage  116  includes, in the example shown, a linear stage assembly  204 . In one example, the linear stage assembly includes X, Y, and Z linear stages configured to position the sample stage surface  208  along one or more of the linear axes. Additionally, the multiple degree of freedom sample stage  116  optionally includes a rotation and tilt stage assembly  206  coupled with the linear stage assembly  204 . In one example, the rotation and tilt stage assembly  206  is coupled in series with the linear stage assembly  204 . In another example, one or more of the rotation and tilt stages is interposed between one or more of the linear stages of the linear stage assembly  204 . 
     In yet another example, the mechanical testing instrument  114  is coupled with the testing assembly platform  200  with a mechanical testing instrument linear stage  210  (e.g., a stage configured to move the instrument relatively along an axis, such as the X axis j interposed therebetween. In one example, the mechanical testing instrument linear stage  210  includes one or more linear stages (one or more of X, Y or Z linear stages) configured to move the mechanical testing instrument  114  relative to the sample stage surface  208  as well as one or more of the first through fourth instruments  104 - 110 . 
     As further shown in  FIG. 2 , actuation and sensing cabling  212  extends to one or more portions of the testing assembly  112 , for instance to each of the linear stages of the linear stage assembly  204  as well as each of the rotation and tilt stages of the rotation and tilt stage assembly  206 . Additionally, in another example actuation and sensing cabling  212  is provided for the mechanical testing instrument  114 , as well as the mechanical testing instrument linear stage  210 . The actuation and sensing cabling  212  facilitates the actuation of each of the one or more stages, the mechanical testing instrument or the like. In another example, the actuation and sensing cabling  212  is coupled with encoders provided with each of the stages of the linear stage assembly  204 , the rotation and tilt stage assembly  206 , and the mechanical testing instrument linear stage  210  to facilitate the accurate actuation and positioning and orientation measurement of the instruments and sample stage surface  208  as described herein. 
     Further, the multiple degree of freedom sample stage  116  is configured to position the sample stage surface  208  within a coincidence region of the instruments  110  (e.g., where the focal points of the one or more instruments  104 - 110  are aligned or coincident) without undesired collision with any of the instruments  104 - 110  and the mechanical testing instrument  114 . Optionally, the mechanical testing instrument  114  on the mechanical testing instrument linear stage  210  is configured to cooperate with movement of the sample stage (e.g., the multiple degree of freedom sample stage  116 ) to ensure mechanical testing interaction is possible with the sample stage surface  208  in a variety of orientations. In some examples, the movement of the mechanical testing instrument  114  and the sample stage cooperate to align the sample with one or more the instruments  104 - 110 . For instance, a sample is aligned with the mechanical testing instrument  114  while the sample is also oriented relative to one or more of the instruments  104 - 110 . 
       FIG. 3  is a detailed perspective view of the testing assembly shown in  FIG. 2 . The testing assembly  112  includes the mechanical testing instrument  114 . The instrument  114  is configured to engage with and test a sample  300  coupled with the sample stage surface  208  to test one or more mechanical or electromechanical properties of the sample  300 . In some examples, the sample  300  includes one or more of metal, alloy, polymer, ceramic, glass, composite, semiconductor, biological samples or the like. 
     The mechanical testing instrument  114  includes a probe  310  having a probe tip  320 . The probe  310  selectively engages with (e.g., indents, scratches, or the like) the sample  300  to measure one or more of force, deformation (indentation depth) or the like, for instance to assess one or more properties (e.g., hardness, Young&#39;s modulus, or the like) of the sample  300 . In another example, the instrument  114  includes a clamping member to selectively couple with the sample  300  and the instrument  114  applies a tensile force to the sample  300  to test one or more properties (e.g., tensile strength, Poisson&#39;s ratio, or the like) of the sample  300 . 
     As further shown in  FIG. 3 , the testing assembly  112  includes a heating jacket  330  configured to heat one or more portions of the mechanical testing instrument  114  In one example, the heating jacket  330  heats the probe  310  including at least the probe tip  320 . In another example, the heating jacket  330  optionally heats a clamping member e.g., one or more jaws of the clamping member) provided with the probe  310 , for instance used in tensile testing. As described in greater detail herein, the heating jacket  330  is coupled to the mechanical testing assembly  114  with one or more jacket support struts  370 . In the example shown in  FIG. 3 , the heating jacket  330  includes a jacket base  340  and a support interface  350 . The one or more jacket support struts  370  are coupled with the fastening interface  350  and couple the heating jacket  330  with the mechanical testing instrument  114 . Additionally, the jacket support struts  370  optionally include one or more conductive members  375 , and the one or more conductive members are in electrical communication with the heating jacket  330  to supply an electrical signal to the heating jacket  330  and thereby energize the heating jacket  330  to generate heat. 
     Heating the one or more portions of the testing assembly  112  (e.g., the probe tip  320 ) minimizes heat transfer between components of the testing assembly  112 . Accordingly, the accuracy of tests performed by the testing assembly  112  is improved. In an example, the sample  300  is coupled with the sample stage  116  (e.g., the sample stage surface  208  shown in  FIG. 2 ). The temperature of the sample  300  is optionally altered, for instance with a heating coil positioned proximate the sample stage surface  208 . In this example, when the sample  300  is heated, and the instrument  114  (e.g., the probe tip  320 ) interacts with the sample  300 , heat transfers from the sample  300  to the mechanical testing instrument  114 . In some examples, the heat transfer between the sample  300  and the instrument  114  affects the accuracy of the test results of the testing assembly  112 . The heat transferred from the sample to the probe tip  320  (or inversely with a cooled sample) lowers the temperature of the sample  300 . In some examples, mechanical or electromechanical properties of the sample  300  vary with the temperature of the sample  300 . Accordingly, the accuracy of the results of the tests performed by the testing assembly  112  is affected by the heat transferred to or from (and subsequent temperature change of) the sample  300 . Additionally, heat transferred to or from the probe (e.g., from the sample) changes the dimensions of the probe and accordingly introduces measurement error in either or both of force or displacement measurements because of expansion or contraction based on the heat transfer. 
     Referring again to  FIG. 3 , the heating jacket  330  minimizes heat transfer from the sample  300  to the mechanical testing instrument  114 . For instance, the heating jacket  330  heats the instrument  114  prior to testing (and optionally during testing) to ensure the temperature of the instrument  114  (e.g., the probe tip  320 ) substantially corresponds with the temperature of the sample  300 . Accordingly, heat transfer between the sample  300  and the instrument  114  is minimized, and the accuracy of the tests performed by the testing assembly  112  is enhanced. 
     As described in greater detail herein, the heating jacket  330  includes a heating element  360  and a jacket base  340 . The heating element  360  extends from the jacket base  340 . As described further herein, the heating element  360  is configured to receive the probe  310 . Additionally, the heating element  360  is mechanically isolated from the probe  310  and the probe tip  320 . For instance, the heating jacket  330  is coupled to the mechanical testing instrument  114 , and the probe  310  is separately coupled to the mechanical testing instrument  114  without physical contact or engagement to the probe  310 . The heating jacket  330  is configured to apply non-contact heat transfer between the jacket  330  and the probe  310 . 
       FIG. 4  is a perspective view of one example of the heating jacket  330 . The heating jacket  330  includes the heating element  360 . As further shown in  FIG. 4 , the heating element  360  includes a jacket wall  400  having interior and exterior surfaces  410 ,  412 . The interior surface  410  of the jacket wall  400  surrounds (e.g., encloses, circumscribes, partially encloses or circumscribes or the like) a probe recess  420  and receives the probe  310  therein For example, the probe  310  is positioned in the probe recess  420  (e.g., as shown in  FIG. 6 ). The probe recess  420  optionally extends through the jacket base  340 , and facilitates the reception of the probe  310  by the heating jacket  330 . As described herein, the jacket wall  400 , for instance the interior surface  410 , includes a jacket profile corresponding to a probe profile to facilitate a proximate but disengaged positioning of the jacket wall  400  relative to the probe  310  to enhance heat transfer of the probe while the probe  310  remains mechanically isolated. 
     In the example shown in  FIG. 4 , the jacket base  340  includes a first end  430 A and a second end  430 B. The one or more jacket support struts  370  are coupled to the first end  430 A and the second end  430 B and position the heating jacket  330  in close proximity to the probe  310  while maintaining mechanical isolation therebetween (e.g., with a probe gap). One or more conductive members  375  associated with the struts  370  deliver power between the first and second ends  430 A,  430 B for operation of the heating jacket  330 . For instance, the conductive members  375  transmit electricity between the first and second ends  430 A,B of the heating jacket  330 . 
     The heating jacket  330  includes, but is not limited to molybdenum disilicide, platinum alloys or the like in a solid core that are optionally machined (e.g., by electrical discharge machining) to provide stress minimizing features to the heating jacket  330 . For instance, a plurality of channels  440  are optionally included in the heating jacket  330  to circuitously route electricity from the first end  430 A to the second end  430 B and thereby resistively heat the heating jacket  330  along the jacket wall  400 . Additionally, the plurality of channels  440  facilitate the tuning of the resistance and thereby heating) of the heating jacket  340  through variation of the cross-sectional area at the various segments  450  and corners  460  of the jacket  330 . Accordingly, the channels  440  facilitate the control of the heat generated by the heating element  360 . Further, the cutouts  440  facilitate the expansion and contraction of the jacket wall  400  in a lateral manner relative to the probe recess  420  while minimizing radial expansion or contraction of the jacket wall  400  and corresponding engagement with the probe. 
       FIG. 5  is a side view of the heating jacket of  FIG. 4 , The heating jacket  330  includes the jacket base  340  and the heating element  360 . As previously described, the heating element  360  (including the jacket wall  400 ) is coupled to the jacket base  340  with a first leg  500 A and a second leg  500 B. The first leg  500 A is in electrical communication with the second leg  500 B through the heating element  360  including in this example the serpentine segments and corners of the jacket wall  400 . Accordingly, an electrical signal transmitted through the first leg  500 A is transmitted through the heating element  360  to the second leg  500 B to initiate heating in the jacket wall  400 . 
       FIG. 6  is a top view of the heating jacket of  FIG. 4  with the probe  310  received in the heating jacket  330 . As shown, the probe  310  is received in the probe recess  420  of the heating jacket  330 . A probe gap  600  is provided between the probe  310  and the heating element  360  (e.g., between the jacket wall  400  and the probe  310 ). The jacket wall  400 , such as the interior surface  410  of the jacket wall  400 , includes a jacket profile  610  corresponding to a probe profile  620  of the probe  310 . The corresponding profiles facilitate the reception of the probe  310 , mechanical isolation of the probe  310 , and at the same time ensure heat generated at the jacket wall  400  is immediately delivered across the intervening probe gap  600  to the probe  310 . In this example, because the heating element  360  is mechanically isolated from the probe  310 , the heating element  360  does not conduct heat to the probe  310 . Instead, the heating element (e.g., the jacket wall  400 ) transfers heat to the probe  310  through one or more non-contact modes of heating, for example radiative or convective modes of heat transfer as well as inductive heating (described herein). 
     As described herein, the jacket wall  400  (shown in  FIG. 4 ) includes the jacket profile  610 . For instance, the jacket profile  610  is substantially circular or cylindrical and corresponds to one or more of the shape, contour or size of the interior surface of the jacket wall  400 . Conversely, the probe  310  includes the probe profile  620 . In the example provided in  FIG. 6 , the probe profile  620  corresponds to the jacket profile  610 . For instance, the jacket profile  610  is substantially circular or cylindrical and includes one or more of a shape, contour or size approximating the probe profile  620 . The correspondence between the jacket profile  610  and the probe profile  620  ensures the probe gap  600  is minimal therebetween while ensuring the probe  310  is mechanically isolated from the jacket wall  400 . In one example, the jacket profile  610  includes dimensions that are slightly larger than the probe profile  620 . Accordingly, the jacket  330  is sized and shaped to receive the probe  310  in the probe recess  420  (shown in  FIG. 4 ). Similarly, the jacket profile is optionally aligned with (e.g., concentrically, axially, or the like) with the probe profile  620  to facilitate the reception of the probe  310  within the probe recess  420 . Accordingly, the correspondence between the jacket profile  610  and the probe profile  620  ensures high fidelity of heat transfer (e.g., with minimal heat transfer loss) while also maintaining mechanical isolation of the jacket  330  from the probe  310 . 
     Referring again to the example shown in  FIG. 6 , the heating element  360  (e.g., the inner surface  410  of the jacket wall  400 ) is in close proximity to the probe  310 . Additionally, the heating element  360  surrounds the probe  310  including one or more of a continuous enclosing of the probe  310 , continuous enclosing with breaks for the channels  440 , continuous enclosing with gaps between discrete portions of the jacket wall  400  (e.g., gaps between posts, elements or the like). The positioning of the jacket wall  400  in close proximity to the probe  310  enhances heat transfer between the heating element  360  and the probe  310 . Additionally, surrounding the probe  310  with the heating element  360  further enhances heat transfer by directing heat from multiple directions toward the probe  310  while at the same time using the heated jacket wall  400  to minimize escape of accumulated heat in the probe  310  (e.g., through gaps). For example, heat transfer is accomplished from multiple directions relative to the probe  310  (e.g., along perimeter of the probe  310  from the interior surface  410 , shown in  FIG. 4 ) while openings in the jacket wall  400  are optionally minimized to correspondingly minimize the escape of heat. 
       FIG. 7  is a side view of another example of a mechanical testing instrument  114 . The mechanical testing instrument  114  includes the probe  310  and another example of the heating jacket  330 . In this example, the heating jacket  330  is coiled around the probe  310  and is mechanically isolated from the probe  310 . For instance, the probe  310  includes the probe profile  620 , and the heating jacket  330  includes the jacket profile  610 . The jacket profile  610  corresponds with the probe profile  620 , and the jacket profile  610  and the probe profile  620  surround a probe gap  600 . The jacket wall  400  is positioned in close proximity to the probe  310  and surrounds (e.g., coils around) the probe  310  to allow for heat transfer (or inductive heating) from multiple directions relative to the probe  310 . 
     Electricity is transmitted to the first leg  500 A and transmitted through the heating jacket  330  to the second leg  500 B. In this example, the heating jacket  330  inductively heats the probe  310  to alter the temperature of the probe  310 . For instance, the transmission of electricity through the heating jacket  330  generates a magnetic field, and the magnetic field correspondingly excites and thereby heats the probe  310 . In this example, the heating jacket  330  is mechanically isolated from the probe  310 , and the heat transfer is a non-contact mode of heat transfer (e.g., inductive heating). 
     In another example, the heating jacket  330  includes a passageway, and a fluid is pumped through the heating jacket  330  to heat or cool the probe  310 . For instance, a chilled fluid (relative to the temperature of the probe  310 ) is pumped into the first leg  500 A and through the heating jacket  330 . The fluid flows through the heating jacket  330  and cools the probe  310  (e.g., through convection or thermal radiation), and the fluid exits the second leg  500 B of the heating jacket  330 , for instance for heating or cooling and is then recirculated through the jacket. 
       FIG. 8  is a perspective view of the mechanical testing instrument of  FIG. 8 . In this example, a shield  800  substantially surrounds the heating jacket  330  to enhance heat transfer to the probe  310 . In one example, the shield  800  reflects infrared energy that is otherwise dissipated by the probe  310 . In another example, the shield  800  directs the magnetic field generated by the heating jacket  330  to enhance the inductive heating of the probe  310 . In yet another example, the shield  800  is positioned proximate the heating jacket  330  shown in  FIG. 3-6  to insulate the probe  310  or to reflect infrared energy generated by the heating element  360  inwardly back toward the element  360  and toward the probe  310 . 
       FIG. 9  shows one example of a method  900  for testing the mechanical properties of a material, including one or more of mechanical testing instrument  114 , the probe  310 , or the heating jacket  330  as described herein. In describing the method  900 , reference is made to one or more components, features, functions and operations previously described herein. Where convenient, reference is made to the components, features, operations and the like with reference numerals. The reference numerals provided are exemplary and are not exclusive. For instance, components, features, functions, operations and the like described in the method  900  include, but are not limited to, the corresponding numbered elements provided herein and other corresponding elements described herein (both numbered and unnumbered) as well as their equivalents. 
     At  910 , a probe  310  of a mechanical testing instrument  114  is positioned. within a probe recess  420  of a heating jacket  330  having a jacket wall  400 . The jacket wall  400  includes a jacket profile  610  corresponding with a probe profile  620  of the probe  310 . The jacket wall  400  is proximate to the probe  310  according to the correspondence of the jacket profile  610  to the probe profile  620 . 
     At  920 , a heating element  360  of the heating jacket  330  is energized. For example, an electrical signal (e.g., current or the like) is delivered to the heating jacket  330  to initiate one or more of resistive heating of the element  360 , induction of the element or the like. 
     At  930 , heat from the jacket wall  400  is directed toward the probe  310  and across a probe gap  600  according to the correspondence of the jacket profile  610  to the probe profile  620  to alter the temperature of the probe  310 . In another example heating includes inductively heating the probe  310  across the probe gap  600  with the magnetic field generated with the jacket  330  (as shown in  FIG. 7 ). 
     At  940 , the method  900  includes moving the probe  310  to perform a mechanical or electromechanical test. In one example, moving the probe  310  includes one or more of translation, rotation or lateral scratching movement within the probe recess  420 , and the jacket wall  400  mechanically isolates the probe  310  with each of the one or more movements. Accordingly, the probe  310  has one or more degrees of freedom relative to the heating jacket  330  (including, but not limited to reciprocating, rotating, or the like). 
     Several options for the method  900  follow. For instance, the probe  310  is engaged with the sample  300 . In an example, engaging the probe  310  with the sample  300  includes applying a force to the probe  310  with the mechanical testing instrument  114 . 
       FIG. 10  is a schematic view of a system  1000  for correcting thermomechanical drift in a mechanical testing assembly. The system  1000  includes a system frame  1010  and the mechanical testing instrument  114 . In some examples, the system frame  1010  corresponds to the testing assembly platform  200  shown in  FIG. 2 . The system  1000  optionally includes an MTI (mechanical testing instrument) actuator  1020  that allows for actuation and positioning of the mechanical testing instrument  114  relative to the system frame  1010  (e.g., in one or more directions, for instance up or down relative to the system frame  1010 ). In some examples, the MTI actuator  1020  corresponds to the mechanical testing instrument linear stage  210  shown in  FIG. 2 . The mechanical testing instrument  114  includes a probe  310 , and the probe  310  is actuated by a probe actuator  1025  (such as a capacitive transducer) to position the probe  310  relative to the instrument  114 . In some examples, a sensor (e.g., a transducer) is included in the probe actuator to determine, for example, a load (e.g., force) applied to the probe  310  or the displacement of the probe  310 . In another example, the probe actuator  1025  includes a transducer that applies one or more specified loads, displacements of the probe  310  and also measures one or more resulting loads, displacements or the like (e.g., actual resulting loads or displacements in contrast to the applied loads or displacements). 
     The system  1000  for correcting thermomechanical drift includes an interferometer system  1030 . As shown in  FIG. 10 , the interferometer system  1030  is coupled with the mechanical testing instrument  114 . In this example, the interferometer system  1030  includes a first interferometer  1040 A and a second interferometer  1040 B. The first interferometer  1040 A is coupled between the probe  310  and a remainder of the mechanical testing instrument  114 . The first interferometer  1040 A determines a probe displacement ΔX F  of the probe  310  relative to the remainder of the mechanical testing instrument  114 . The probe displacement ΔX F  corresponds to the movement of the probe and accordingly provides an accurate representative of the probe movement to measure actual indentation depth or other displacement based values of the probe relative to a sample and the remainder of the mechanical testing instrument. 
     In an example, the first interferometer  1040 A splits a first coherent beam of light into a first component beam and a second component beam. The first coherent beam of light is produced by a light source, for instance a laser generator (e.g., the laser generator  1111  shown in  FIG. 11 ). The first coherent beam of light is transmitted through a medium, for example an optical fiber (e.g., the optical fiber  1120 ) including a fiber end (e.g., a cleaved end  1125  of the optical fiber  1120 , shown in  FIG. 11 ). The first coherent beam of light reaches the fiber end, and is split into the first component beam and the second component beam forming an optical cavity. In sonic examples, the first component beam (e.g., a reference beam) is reflected back from the fiber end, and the second component beam (e.g., an active beam) escapes the optical fiber and is transmitted toward a target (e.g., the probe  310 , or for example, a back side of the probe  310  opposite the probe tip  320 ). The second component beam is reflected off the target and back into the optical fiber. Optionally, the first component beam and the second component beam are combined (e.g., recombined) within the optical fiber, and in some examples the first component beam interferes with the second component beam into an interference signal. 
     An optical detector (e.g., the optical detector  1117  shown in  FIG. 11 ) detects the interference signal. In some examples, the component beams or the coherent beam us modulated with one or more of wavelength modulation, phase modulation, or cavity modulation. The detected component beams (e.g., the interference signal) are processed (e.g., by the synchronous demodulator  1118  shown in  FIG. 11 ) to determine the displacement between the target and the fiber end. In one example, the displacement is determined using fringe counting. Fringe counting includes observing (e.g., with the optical detector) an interference fringe pattern produced by the combined first component beam and the second component beam. In this example, because the combined first component beam and the second component beam are out of phase, interference (e.g., constructive interference or destructive interference) by the component beams produces a fringe pattern (e.g., a gradient of light and dark banding) when observed. The distance between fringes of the fringe pattern is known, for example the distance between light and dark bands of the fringe pattern corresponds to a wavelength of the first coherent light beam. The system  1000  analyzes the fringe pattern and accordingly determine the distance between the fiber end and the target. For instance, the system  1000  counts changes from light to dark banding to determine the change in distance of the target relative to the fiber end. Accordingly, the first interferometer  1040 A allows for a determination of the probe displacement ΔX F  of the probe  310  relative to the remainder of the mechanical testing instrument  114 . Additionally, the probe displacement corresponds in one example to an indentation depth of a tip of the probe  310  into a sample. As described herein, the probe displacement is, in another example, used in combination with displacement of the mechanical testing instrument  114  relative to the system frame  1010  to refine measurements of indentation depth to isolate and remove thermomechanical drift. 
     In another example, the displacement is determined using quadrature detection where the quadrature point is detected in the fringe pattern. For instance, the quadrature point (e.g., inflection point, or the midway point between constructive interference and destructive interference of the combined component beams) provides maximum sensitivity to changes in distance between the fiber end and the target. 
     The second interferometer  1040 B is coupled between the mechanical testing instrument  114  and the system frame  1010 . The second interferometer determines a sample displacement ΔXD of the sample stage (e.g., the sample stage  116  shown in  FIGS. 1-3 ) or the sample  300  relative to the mechanical testing instrument  114 . For instance, the second interferometer  1040 B splits a second coherent beam of light into a third component beam (e.g., the reference beam) and a fourth component beam (e.g., the active beam). Optionally, the third component beam and the fourth component beam are combined into an interference signal. The interference signal is detected and processed to determine the displacement between the second laser interferometer  1040 B (e.g., a fiber end) and the sample stage or the sample  300 . This facilitates precise and accurate measurement of the position (and movement) of the mechanical testing instrument  114  relative to the sample stage and the system frame  1010 . 
     Referring again to  FIG. 10 , the system  1000  for correcting thermomechanical drift includes an isolation and measurement module  1050  in communication with the interferometer system  1030 . The module  1050  optionally includes a processing unit (e.g., an ASIC, CPU, or the like) that processes data received from the interferometer system  1030 . In an example, the module  1050  determines a difference between the probe displacement ΔX F  and the sample displacement ΔX D . The module  1050  facilitates the isolation of the mechanical testing instrument  114  from the thermomechanical drift of the system frame  1000  by using the determined difference between the probe displacement ΔX F  and the sample displacement ΔX D . For instance, the thermomechanical drift of the system frame  1000  affects the determination of the displacement of an indentation depth of the probe  114  relative to the sample  300 . For example, the system  1000  will read a variable indentation depth or force over a period of time due to the thermomechanical drift of the system frame  1010  and corresponding fluctuations caused by expansion or contraction of the frame  1010 . In the example shown in  FIG. 10 , because the first interferometer  1040 A is coupled between the probe  310  and the remainder of the instrument  1040  the interferometer  1040 A measures displacement of the probe  310  relative to the instrument  1040 . Further, because the second interferometer  1040 B is coupled between the instrument  114  and the sample  300  (or the sample stage) the second interferometer  1040 B measures the displacement of the sample  300  relative to the mechanical testing instrument  1040 . The difference between the probe displacement ΔX F  and the sample displacement ΔX D  corresponds to the actual displacement of the probe (e.g., indentation depth or the like) relative to the sample without inclusion of the thermomechanical drift of the system frame  1010 . Stated another way, by coupling the interferometer system with the mechanical testing instrument  1040  and measuring the position of the probe  310  and the sample  300  the system frame  1010  and any thermomechanical drift of the frame  1010  are effectively isolated and removed from consideration. Accordingly, the thermomechanical drift of the system frame  1010  is isolated by and removed by the system  1000  to enhance the precision and accuracy of the determined indentation depth of the probe  140  relative to the sample  300 . 
     In another example, the systems and methods described herein minimize (e.g., minimize or eliminate) thermomechanical drift in one or more of the mechanical testing instrument, sample stage or the like. As described herein, the probe  310  is optionally engaged with the sample  300  to determine one or more characteristics of the sample  300  according to a displacement of the probe  310  (indentation depth, tensile retraction or the like) and a load applied to the sample  300 . The mechanical testing instrument  114 , the sample  300 , or the sample stage (e.g., the multiple degree of freedom sample stage  116 ) are subject to thermomechanical drift. The system  1000  optionally facilitates correction of thermomechanical drift in these components. In an example, the thermomechanical drift is corrected actively or passively. For instance, thermomechanical drift is actively corrected during the test at the interface of the probe  310  to the sample  300  (e.g., at engagement and testing). In another example, the thermomechanical drift experienced during measurements is passively isolated and removed after the test. 
     In an example, the thermomechanical drift is actively corrected by translational driving (e.g., repositioning or actuating) of one or more of the probe  310  or the sample  300  in a compensation (e.g., inverse) scheme relative to the thermomechanical drift that corresponds to a determined displacement. In an example, the probe  310  is translated (e.g., actuated) to counteract (e.g., cancel, minimize, counterbalance, or the like) the thermomechanical drift. For example, the sample  300  translates due to thermomechanical drift in the sample stage or the system frame  1000 . The probe  310  is translationally driven to correct (e.g., chase, follow, cancel out, or the like) the drift of the sample  300 . Accordingly, the system  1000  improves the accuracy of determining the one or more characteristics of the sample  300 . In another example, the thermomechanical drift causes the load sensed by the sensor to fluctuate (e.g., the force between the probe  310  and the sample varies because the position of the sample  300  relative to the probe  310  changes with the thermomechanical drift). In this example, the thermomechanical drift is corrected by varying the load to compensate for the thermomechanical drift and accordingly the load is consistently applied to the probe  310  or the sample  300 . 
     In yet another example, the thermomechanical drift is passively corrected by subtraction of detected thermomechanical drift from the measured displacement of the probe  310  or the determined one or more characteristics of the sample  300 . For instance, the probe  310  is engaged with the sample  300  and displaced relative to the sample by applying a load to the probe  310 . The displacement of the probe  310  is measured (e.g., with a sensor, for example a transducer). The determined thermomechanical drift is subtracted from displacement of the probe  310 , and the accuracy of the measured displacement of the probe  310  is thereby improved. In another example, the fluctuation corresponding to thermomechanical drift is utilized to correct the measured load by subtracting the load fluctuations attributed to the thermomechanical drift. 
       FIG. 11  is a schematic view of the interferometer system  1030 . The interferometer system  1030  includes a laser source  1111  that generates a coherent light beam (e.g., a light beam that includes a specified wavelength). Additionally, the system  1030  includes an optical fiber  1120  coupled with the laser source  1111 . The optical fiber  1120  is optionally coupled with one or more components of the system  1030  to facilitate the transmission of one or more beams of light between the components. In an example, the optical fiber  1120  optically couples the laser source  1111 , a circulator  1112 , a fiber stretcher  1113 , an electromechanical oscillator  1114 , and an optical detector  1117 . 
     The circulator  1112  facilitates the transmission of optical signals within the system  1030 . For instance, the circulator  1112  optionally directs the first coherent beam of light from the laser generator  1030  toward the target  1030 . Additionally, the circulator  1112  optionally directs the first component beam and the second component beam (described herein) toward the optical detector  1117 . 
     The fiber stretcher  1113  dynamically stretches the optical fiber  1120  to change a path length of one or more beams of light as the beams are transmitted through the optical fiber (e.g., the first coherent beam or the first and second component beams). The optical fiber  1120  includes a temperature sensitivity characteristic that causes a low frequency thermomechanical drift in measurements conducted with the system  1030 . The fiber stretcher  1113  shifts the low frequency measurement to a higher frequency domain, where the higher frequency value is readily filtered to correct for thermomechanical drift within the system  1030 . 
     In an example, the optical fiber  1120  is optionally wrapped around a piezoelectric element that expands and contracts with an application of current to the piezoelectric element. In this example, because the optical fiber  1120  is wrapped around the piezoelectric element, and the piezoelectric element expands and contracts, the path length of the optical fiber  1120  is correspondingly lengthened and shortened by the expansion and contraction of the piezoelectric element. A resonator  1115  is in communication with the fiber stretcher  1113  and supplies an electrical signal to the fiber stretcher  1113  to dynamically stretch the optical fiber  1120  (e.g., at several kilohertz). 
     As described herein, the system  1030  optionally includes the electromechanical oscillator  1114 . The electromechanical oscillator  1114  modulates a cavity length (e.g., the distance between a fiber end  1125  and the target  130 ) that in turn modulates the interference signal (e.g., the interference signal is not purely sinusoidal). In an example, the optical fiber  1120  includes the fiber end  1125 . The fiber end  1125  is optionally coupled with the electromechanical oscillator  1114  and the electromechanical oscillator  1114  modulates (e.g., oscillates, vibrates, or the like) the fiber end  1125  at a specified frequency and a specified amplitude. In an example, the modulation amplitude of the fiber end  1125  so that an amplitude of a demodulated interference signal at an operating frequency is equal to the amplitude of demodulated interference signal at double the operating frequency (e.g., the first harmonic). In another example, the fiber end  1125  modulates at a different multiple frequency of the operating frequency of the fiber stretcher  1113 . 
     Referring again to  FIG. 11 , the fiber end  1125  is directed at the target  1130  to deliver the component beam (e.g., the second component beam, or active beam) toward the target  1130 . The modulation of the fiber end  1125  by the electromechanical oscillator  1114  modulates the distance between the fiber end  1125  and the target  1130 . Accordingly, the signal received by the optical detector  1117  (e.g., the combined first and second component beams) is modulated. Modulating the fiber end  1125  facilitates the removal of signal noise and improves the determination of the displacement between the fiber end  1125  and the target  1130  (e.g., between the second interferometer  1040 B and the sample  300  shown in  FIG. 3 ). 
     In an example, the synchronous demodulator  1118  samples the optical detector  1117  at the same frequency that the electromechanical oscillator  1114  modulates the fiber end  1125 . In this example, because the fiber end  1125  is modulated, and the signal received by the optical detector  1117  is correspondingly modulated, synchronously demodulating the signal extends a displacement detection range between the fiber end  1125  and the target  1130  beyond single fringe interferometry. Accordingly, the determination of the distance (or displacement) of the target relative to the fiber end  1125  is thereby improved (e.g., the signal-to-noise ratio of the combined component beams is improved). 
       FIG. 12  shows one example of a method  1200  for correcting thermomechanical drift with a mechanical testing assembly having a sample stage and a mechanical testing instrument. In describing the method  1200 , reference is made to one or more components, features, functions and operations previously described herein. Where convenient, reference is made to the components, features, operations and the like with reference numerals. The reference numerals provided are exemplary and are not exclusive. For instance, components, features, functions, operations and the like described in the method  1200  include, but are not limited to, the corresponding numbered elements provided herein and other corresponding elements described herein (both numbered and unnumbered) as well as their equivalents. 
     At  1210 , a probe  310  of the mechanical testing instrument  114  is engaged with a sample  300  coupled with the sample stage (e.g., the multiple degree of freedom sample stage  116 ), wherein one or more of the mechanical testing instrument, the sample or the sample stage are subject to thermomechanical drift. At  1220 , the engaged probe  310  is displaced relative to the sample  300  with a load. At  1230 , one or more of the displacement or the load is measured. At  1240 , one or more characteristics of the sample are determined with the probe according to the displacement and the load. 
     At  1250 , the thermomechanical drift is corrected in one or more of the measured displacement of the probe with the sample (e.g., indentation depth, retraction length or the like) or the determined one or more characteristics. At  1260 , correcting for the thermomechanical drift includes independently measuring a displacement of the probe relative to the system frame and independently measuring a displacement of the sample relative to the system frame with non-contact sensors. Several options for the method  1200  follow. In one example, correcting for the thermomechanical drift includes splitting a coherent beam of light from a laser source into at least first and second component beams. Additionally, correcting for the thermomechanical drift optionally includes directing the first component beam from a fiber end  1025  of a fiber  1020  against one of the mechanical testing instrument  114 , sample  300  or the sample stage. Further, correcting for the thermomechanical drift optionally includes combining the first and second component beams. Still further, correcting for the thermomechanical drift optionally includes determining a differential displacement between the probe and the sample, and the phase difference corresponds to the thermomechanical drift of a component, such as the system frame  1010  where the fiber end  1025  is coupled with the mechanical testing instrument  114  (or  1040 ) and detects movement of the sample  300  (corresponding to the system frame  1010 ). 
     In one example, the method  1200  includes determining a displacement of the probe  310 . For instance, a first interferometer is directed towards one of the probe  310  or an instrument housing of (e.g., the remainder of) the mechanical testing instrument  114  (or  1040 ). The second interferometer measures the displacement of the probe  310  relative to the remainder of the mechanical testing instrument  114  (or  1040 ). The difference (corresponding to thermomechanical drift of the system frame  1010  in an example) is used to determine the displacement of the probe  310  relative to the sample  300  and thereby isolate and remove thermomechanical drift. 
     Various Notes &amp; Examples 
     Aspect 1 can include or use subject matter (such as an apparatus, a system, a device, a method, a means for performing acts, or a device readable medium including instructions that, when performed by the device, can cause the device to perform acts, or an article of manufacture), such as can include or use a probe heating jacket configured for heating a mechanical testing instrument having a probe, the probe heating jacket comprising: at least one fastening interface configured for coupling with the mechanical testing instrument; and a heating element extending from the at least one fastening interface, the heating element includes: a jacket wall coupled with the at least one fastening interface; and the jacket wall extends around a probe recess, the jacket wall is configured to receive the probe of the mechanical testing instrument within the probe recess, and the heating element is mechanically isolated from the probe with a probe gap. 
     Aspect 2 can include or use, or can optionally be combined with the subject matter of Aspect 1, to optionally include or use wherein the jacket wall includes an interior surface facing the probe recess, and the interior surface is configured to direct heat across the probe gap to the probe. 
     Aspect 3 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 1 or 2 to optionally include or use wherein the jacket wall is a radiative heating element. 
     Aspect 4 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 1 through 3 to optionally include or use wherein the jacket wall is an inductive heating element. 
     Aspect 5 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 1 through 3 to optionally include or use the mechanical testing instrument and the probe. 
     Aspect 6 can include or use, or can optionally be combined with the subject matter of Aspect 5 to optionally include or use wherein the probe is received in the probe recess of the jacket wall, the probe is mechanically isolated from the heating element, and the probe is spaced from the interior surface of the jacket wall by the probe gap. 
     Aspect 7 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 5 or 6 to optionally include or use wherein the mechanical testing instrument is configured to move the probe within the probe recess, the probe movement mechanically isolated from the jacket wall. 
     Aspect 8 can include or use, or can optionally be combined with the subject matter of Aspect 7 to optionally include or use wherein the probe has one or more degrees of freedom relative to the heating jacket. 
     Aspect 9 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 5 through 8 to optionally include or use wherein: the jacket wall includes a jacket profile; the probe includes a probe profile, and the probe profile corresponds with the jacket profile with the probe gap therebetween the heating element and the probe; and the jacket wall is in proximity to the probe, and surrounds the probe according to the corresponding jacket and probe profiles. 
     Aspect 10 can include or use subject matter (such as an apparatus, a system, a device, a method, a means for performing acts, or a device readable medium including instructions that, when performed by the device, can cause the device to perform acts, or an article of manufacture), such as can include or use a mechanical testing system, comprising: a mechanical testing instrument having a movable probe configured to test one or more mechanical properties of a sample of a material; a probe heating jacket configured for heating the mechanical testing system, the probe heating jacket including: at least one fastening interface configured for coupling with the mechanical testing instrument; a heating element extending from the at least one fastening interface, the heating element includes: a jacket wall coupled with the at least one fastening interface, the jacket wall extends around a probe recess, the jacket wall is configured to receive a probe of the mechanical testing instrument within the probe recess, and the heating element is mechanically isolated from the probe with a probe gap. 
     Aspect 11 can include or use, or can optionally be combined with the subject matter of Aspect 10, to optionally include or use wherein the mechanical testing system is configured to move the probe within the probe recess, the probe movement mechanically isolated from the jacket wall. 
     Aspect 12 can include or use, or can optionally be combined with the subject matter of Aspect 11 to optionally include or use wherein probe movement includes one or more of translation, rotation or lateral scratching movement within the probe recess, and the jacket wall mechanically isolates the probe with each of the one or more movements. 
     Aspect 13 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 10 through 12 to optionally include or use wherein: the jacket wall includes a jacket profile; the probe includes a probe profile, and the probe profile corresponds with the jacket profile with the probe gap therebetween the heating element and the probe; and the jacket wall is in proximity to the probe, and surrounds the probe according to the corresponding jacket and probe profiles. 
     Aspect 14 can include or use, or can optionally be combined with the subject matter of Aspect 13 to optionally include or use wherein the heating element is a radiative heating element, a convective heating element, or an inductive heating element. 
     Aspect 15 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 10 through 14 to optionally include or use an environmental conditioning chamber, wherein the chamber is configured to provide a conditioned environment, and the conditioned environment has one or more environmental characteristics that are different than a surrounding environment of the chamber. 
     Aspect 16 can include or use, or can optionally be combined with the subject matter of Aspect 15 to optionally include or use wherein the one or more environmental characteristics includes: temperature, pressure, humidity or fluid composition. 
     Aspect 17 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 15 or 16 to optionally include or use wherein the probe heating jacket is positioned in the environmental conditioning chamber. 
     Aspect 18 can include or use subject matter (such as an apparatus, a system, a device, a method, a means for performing acts, or a device readable medium including instructions that, when performed by the device, can cause the device to perform acts, or an article of manufacture), such as can include or use a method for testing the mechanical properties of a material, comprising: positioning a probe of a mechanical testing instrument within a probe recess of a probe heating jacket having a jacket wall, wherein the jacket wall includes a jacket profile corresponding with a probe profile of the probe, and the jacket wall is proximate to the probe according to the correspondence of the jacket profile to the probe profile; energizing a heating element of the probe heating jacket; directing heat from the jacket wall to the probe through a probe gap according to the correspondence of the jacket profile to the probe profile to alter the temperature of the probe; moving the probe to perform a mechanical or electromechanical test; and wherein during movement of the probe, the probe is mechanically isolated from the jacket wall. 
     Aspect 19 can include or use, or can optionally be combined with the subject matter of Aspect 18, to optionally include or use wherein moving the probe includes one or more of translation, rotation or lateral scratching movement within the probe recess, and the jacket wall mechanically isolates the probe with each of the one or more movements. 
     Aspect 20 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 18 or 19 to optionally include or use engaging the probe with a sample of a material. 
     Aspect 21 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 18 through 20 to optionally include or use wherein engaging the probe with the sample includes applying a force to the probe with a mechanical testing instrument. 
     Aspect 22 can include or use subject matter (such as an apparatus, a system, a device, a method, a means for performing acts, or a device readable medium including instructions that, when performed by the device, can cause the device to perform acts, or an article of manufacture), such as can include or use a method for correcting for thermomechanical drift with a mechanical testing assembly having a sample stage and a mechanical testing instrument coupled to a system frame, the method comprising: engaging a probe of the mechanical testing instrument with a sample coupled with the sample stage, one or more of the mechanical testing instrument, the sample or the sample stage are subject to thermomechanical drift; displacing the engaged probe relative to the sample with a load; measuring one or more of the displacement or the load; determining one or more characteristics of the sample with the probe according to the displacement and the load; and correcting for the thermomechanical drift in one or more of the measured displacing of the probe with the sample or the determined one or more characteristics, correcting includes: independently measuring a displacement of the probe relative to the system frame and independently measuring a displacement of the sample relative to the system frame with non-contact sensors. 
     Aspect 23 can include or use, or can optionally be combined with the subject matter of Aspect 22, to optionally include or use wherein measuring the displacement of the probe or the displacement of the sample includes one or more of quadrature detection or fringe counting. 
     Aspect 24 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 22 or 23 to optionally include or use wherein the non-contact sensors include one or more of a laser interferometer, a fiber light displacement sensor, a confocal sensor, or a capacitance sensor. 
     Aspect 25 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 22 through 24 to optionally include or use wherein the non-contact sensor is a laser interferometer, and the independently measuring includes: generating a coherent beam of light into one or more optical fibers; transmitting the coherent beam of light through the one or more optical fibers to a fiber end; splitting the coherent beam of light into a first component beam and a second component beam; reflecting the first component beam off a fiber interface with a medium; reflecting the second component beam off the sample, the sample stage, or the mechanical testing instrument; and combining the first component beam and the second component beam at an optical detector; and determining a displacement of the sample, the sample stage, or the mechanical testing instrument relative to the system frame by synchronously demodulating the combined first component beam and the second component beam. 
     Aspect 26 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 22 through 25 to optionally include or use wherein correcting for the thermomechanical drift includes at least one of active or passive correction for the engagement of the probe with the sample or measurement of the one or more characteristics, respectively. 
     Aspect 27 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 22 through 26 to optionally include or use wherein correcting for the thermomechanical drift includes active correction for thermomechanical drift including translational driving of one or more of the probe or the sample in order to cancel out the thermomechanical drift. 
     Aspect 28 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 22 through 27 to optionally include or use wherein correcting for the thermomechanical drift includes passive correction for thermomechanical drift including subtraction of the thermomechanical drift during the determining of the one or more characteristics of the sample. 
     Aspect 29 can include or use subject matter (such as an apparatus, a system, a device, a method, a means for performing acts, or a device readable medium including instructions that, when performed by the device, can cause the device to perform acts, or an article of manufacture), such as can include or use a system to correct for thermomechanical drift in a mechanical testing assembly, comprising: a system frame, wherein the system frame is subject to thermomechanical drift; a sample stage coupled with the system frame; a mechanical testing instrument coupled with the system frame, the mechanical testing instrument includes a movable probe configured to engage with a sample and displace a depth relative to the sample with a load; a laser interferometer system coupled with the mechanical testing instrument, the laser interferometer system includes: a first interferometer coupled between the probe and a remainder of the mechanical testing instrument, the first interferometer is configured to determine a probe displacement of the probe relative to the remainder of the mechanical testing instrument; a second interferometer coupled between the mechanical testing instrument and the system frame, the second interferometer is configured to determine a sample displacement of the sample stage or the sample relative to the mechanical testing instrument; and an isolation and measurement module configured to: determine a difference between the probe displacement and the sample displacement; isolate the mechanical testing instrument from the thermomechanical drift of the system frame using the determined difference between the probe displacement and the sample displacement. 
     Aspect 30 can include or use, or can optionally be combined with the subject matter of Aspect 29, to optionally include or use an electromechanical oscillator configured to oscillate a first fiber end or the second fiber end to provide a modulated optical signal. 
     Aspect 31 can include or use, or can optionally be combined with the subject matter of one or any combination of Aspects 29 or 30 to optionally include or use a fiber stretcher configured to dynamically stretch a fiber of the first interferometer or the second interferometer to mitigate thermally induced drift within the fiber. 
     Aspect 32 can include or use, or can optionally be combined with the subject matter of Aspect 31 to optionally include or use wherein the fiber stretcher includes an electromechanical element. 
     Aspect 33 can include or use, or can optionally be combined with any portion or combination of any portions of any one or more of Aspects 1 through 33 to include or use, subject matter that can include means for performing any one or more of the functions of Examples 1 through 20, or a machine-readable medium including instructions that, when performed by a machine, cause the machine to perform any one or more of the functions of Examples 1 through 20. 
     Each of these non-limiting examples can stand on its own, or can be combined in various permutations or combinations with one or more of the other examples. 
     The above description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein. 
     In the event of inconsistent usages between this document and any documents so incorporated by reference, the usage in this document controls. 
     In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. 
     Geometric terms, such as “parallel”, “perpendicular”, “round”, or “square”, are not intended to require absolute mathematical precision, unless the context indicates otherwise. Instead, such geometric terms allow for variations due to manufacturing or equivalent functions. For example, if an element is described as “round” or “generally round,” a component that is not precisely circular (e.g., one that is slightly oblong or is a many-sided polygon) is still encompassed by this description. 
     Method examples described herein can be machine or computer-implemented at least in part, Some examples can include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples, An implementation of such methods can include code, such as microcode, assembly language code, a higher-level language code, or the like. Such code can include computer readable instructions for performing various methods. The code may form portions of computer program products. Further, in an example, the code can be tangibly stored on one or more volatile, non-transitory, or non-volatile tangible computer-readable media, such as during execution or at other times. Examples of these tangible computer-readable media can include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memories (RAMs), read only memories (ROMs), and the like. 
     The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.