Patent Publication Number: US-10766065-B2

Title: Method and assembly for a multiple component core assembly

Description:
BACKGROUND 
     The field of the disclosure relates generally to forming components via casting, and more particularly to forming a multiple component core assembly for casting such components. 
     Some known methods for manufacturing metallic components include casting. Some known casting methods facilitate the production of near net shaped components where the component is substantially formed in one step during the casting process and finish machined to complete the component. At least some components include intricately-shaped voids and internal passages and/or require an interior surface to be formed with particular features. For example, but not by way of limitation, some components, such as hot gas path components of gas turbines, are subjected to high temperatures. At least some such components have intricately-shaped internal voids defined therein, such as but not limited to a network of plenums and passages, to receive a flow of a cooling fluid adjacent an outer wall. 
     At least some such known components are formed in a mold with a core of ceramic material positioned within the mold cavity. A molten metal alloy is introduced to the mold cavity around the ceramic core and cooled to form the component. However, an ability to produce intricately-shaped voids and/or internal passages of the cast component depends on an ability to precisely form the intricate core and position it relative to the mold to define the cavity space between the core and the mold. In addition, at least some known ceramic cores are fragile, resulting in cores that are difficult and expensive to produce and handle without damage during the mold creation and casting process. 
     Alternatively or additionally, at least some known components are formed by drilling and/or otherwise machining the component to obtain the final shape, such as, but not limited to, using an electrochemical machining process. However, at least some such machining processes are relatively time-consuming and expensive. Moreover, at least some such machining processes cannot produce an outer wall having the features, wall thickness, shape, and/or contours required for certain component designs. 
     BRIEF DESCRIPTION 
     In one aspect, a mold assembly for forming a component from a component material is provided. The mold assembly includes a mold having an interior wall that defines a mold cavity within the mold. The mold cavity is configured to receive the component material in a molten state therein. The mold assembly also includes a core assembly that is positioned with respect to the mold. The core assembly includes a first core component, a second core component separate from the first core component, and a core connection component coupled to the first core component and the second core component. The first core component is coupled adjacent the second core component at a core split line defined therebetween. Additionally, the core connection component is formed from a connection component material that is configured to be absorbable by the component material. 
     In another aspect, a method of forming a component is provided. The method includes positioning a core assembly with respect to a cavity defined in a mold. The core assembly includes at least two separate core components, and a core connection component coupled to the at least two individual core components. The at least two individual core components are coupled to each other at a core split line defined therebetween. In addition, the method includes introducing a component material in a fluid state into the cavity, such that the core connection component is at least partially absorbed by the component material. 
    
    
     
       DRAWINGS 
       These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a schematic diagram of an exemplary rotary machine; 
         FIG. 2  is a schematic perspective view of an exemplary component for use with the rotary machine shown in  FIG. 1 ; 
         FIG. 3  is a schematic cross-section of the component shown in  FIG. 2 , taken along lines  3 - 3  shown in  FIG. 2 ; 
         FIG. 4  is a schematic exploded perspective view of a multiple component core assembly defining a cooling circuit of the component shown in  FIGS. 3 and 4 ; 
         FIG. 5  is a schematic perspective view of the multiple component core assembly coupled together with exemplary core connection components; 
         FIG. 6  is a schematic sectional view of an exemplary core split line of the exemplary multiple component core assembly of  FIGS. 4 and 5 , taken along line  6 - 6  in  FIG. 5 ; 
         FIG. 7  is a schematic view of an exemplary mold assembly that includes the multiple component core assembly of  FIGS. 4-6 , and is used to form the component shown in  FIG. 2 ; 
         FIG. 8  is a flow diagram of an exemplary method of forming the component shown in  FIG. 2 ; 
         FIG. 9  is a schematic view of an alternative exemplary core split line of the exemplary multiple component core assembly of  FIGS. 4 and 5 ; 
         FIG. 10  is a schematic view of another alternative exemplary core split line of the exemplary multiple component core assembly of  FIGS. 4 and 5 ; 
         FIG. 11  is a schematic view of another alternative exemplary core split line of the exemplary multiple component core assembly of  FIGS. 4 and 5 ; 
         FIG. 12  is a schematic view of another alternative exemplary core split line of the exemplary multiple component core assembly of  FIGS. 4 and 5 ; and 
         FIG. 13  is a schematic view of another alternative exemplary core split line of the exemplary multiple component core assembly of  FIGS. 4 and 5 . 
     
    
    
     Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of the disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of the disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein. 
     DETAILED DESCRIPTION 
     In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings. 
     The singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. 
     “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not. 
     Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms such as “about,” “approximately,” and “substantially” is not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be identified. Such ranges may be combined and/or interchanged, and include all the sub-ranges contained therein unless context or language indicates otherwise. 
     The exemplary components and methods described herein overcome at least some of the disadvantages associated with known assemblies and methods for forming cast components. The embodiments described herein include separately forming at least two core components shaped to correspond to at least portions of an interior void of the component, and coupling the core components together using a core connection component. The pattern assembly is encased in a pattern material. The encased core assembly is used to fabricate a mold. The pattern material is removed to form a cavity within the mold. The component is cast in the mold cavity defined between the pattern assembly and the walls of the mold. When a molten or fluid component material is added to the mold, the core connection component is absorbed by the component material. The at least two core components are removed from the component to define the interior void of the component therein. 
       FIG. 1  is a schematic view of an exemplary rotary machine  10  having components for which embodiments of the current disclosure may be used. In the exemplary embodiment, rotary machine  10  is a gas turbine that includes an intake section  12 , a compressor section  14  coupled downstream from intake section  12 , a combustor section  16  coupled downstream from compressor section  14 , a turbine section  18  coupled downstream from combustor section  16 , and an exhaust section  20  coupled downstream from turbine section  18 . A generally tubular casing  36  at least partially encloses one or more of intake section  12 , compressor section  14 , combustor section  16 , turbine section  18 , and exhaust section  20 . In alternative embodiments, rotary machine  10  is any rotary machine for which components formed with internal passages as described herein are suitable. Moreover, although embodiments of the present disclosure are described in the context of a rotary machine for purposes of illustration, it should be understood that the embodiments described herein are applicable in any context that involves a component suitably formed. 
     In the exemplary embodiment, turbine section  18  is coupled to compressor section  14  via a rotor shaft  22 . It should be noted that, as used herein, the term “couple” is not limited to a direct mechanical, electrical, and/or communication connection between components, but may also include an indirect mechanical, electrical, and/or communication connection between multiple components. 
     During operation of gas turbine  10 , intake section  12  channels air towards compressor section  14 . Compressor section  14  compresses the air to a higher pressure and temperature. More specifically, rotor shaft  22  imparts rotational energy to at least one circumferential row of compressor blades  40  coupled to rotor shaft  22  within compressor section  14 . In the exemplary embodiment, each row of compressor blades  40  is preceded by a circumferential row of compressor stator vanes  42  extending radially inward from casing  36  that direct the air flow into compressor blades  40 . The rotational energy of compressor blades  40  increases a pressure and temperature of the air. Compressor section  14  discharges the compressed air towards combustor section  16 . 
     In combustor section  16 , the compressed air is mixed with fuel and ignited to generate combustion gases that are channeled towards turbine section  18 . More specifically, combustor section  16  includes at least one combustor  24 , in which a fuel, for example, natural gas and/or fuel oil, is injected into the air flow, and the fuel-air mixture is ignited to generate high temperature combustion gases that are channeled towards turbine section  18 . 
     Turbine section  18  converts the thermal energy from the combustion gas stream to mechanical rotational energy. More specifically, the combustion gases impart rotational energy to at least one circumferential row of rotor blades  70  coupled to rotor shaft  22  within turbine section  18 . In the exemplary embodiment, each row of rotor blades  70  is preceded by a circumferential row of turbine stator vanes  72  extending radially inward from casing  36  that direct the combustion gases into rotor blades  70 . Rotor shaft  22  may be coupled to a load (not shown) such as, but not limited to, an electrical generator and/or a mechanical drive application. The exhausted combustion gases flow downstream from turbine section  18  into exhaust section  20 . Components of rotary machine  10  are designated as components  80 . Components  80  proximate a path of the combustion gases are subjected to high temperatures during operation of rotary machine  10 . Additionally or alternatively, components  80  include any component suitably formed as described herein. 
       FIG. 2  is a schematic perspective view of an exemplary component  80 , illustrated for use with rotary machine  10  (shown in  FIG. 1 ).  FIG. 3  is a schematic cross-section of component  80 , taken along line  3 - 3  shown in  FIG. 2 . In the exemplary embodiment, component  80  includes an outer wall  94 . Moreover, in the exemplary embodiment, component  80  includes at least one internal void  100  defined therein. For example, a cooling fluid is provided to internal void  100  during operation of rotary machine  10  to facilitate maintaining component  80  below a temperature of the hot combustion gases. 
     Component  80  is formed from a component material  78 . In the exemplary embodiment, component material  78  is a suitable nickel-based superalloy. In alternative embodiments, component material  78  is at least one of a cobalt-based superalloy, an iron-based alloy, and a titanium-based alloy. In other alternative embodiments, component material  78  is any suitable material that enables component  80  to be formed as described herein. 
     In the exemplary embodiment, component  80  is one of rotor blades  70  or stator vanes  72 . In alternative embodiments, component  80  is another suitable component of rotary machine  10  that is capable of being formed as described herein. In still other alternative embodiments, component  80  is any component for any suitable application that is suitably formed as described herein. 
     In the exemplary embodiment, rotor blade  70 , or alternatively stator vane  72 , includes a pressure side  74  and an opposite suction side  76 . Each of pressure side  74  and suction side  76  extends from a leading edge  84  to an opposite trailing edge  86 . In addition, rotor blade  70 , or alternatively stator vane  72 , extends from a root end  88  to an opposite tip end  90 . A longitudinal axis  82  of component  80  is defined between root end  88  and tip end  90 . In alternative embodiments, rotor blade  70 , or alternatively stator vane  72 , has any suitable configuration that is capable of being formed as described herein. 
     Outer wall  94  at least partially defines an exterior surface  92  of component  80 . In the exemplary embodiment, outer wall  94  extends circumferentially between leading edge  84  and trailing edge  86 , and also extends longitudinally between root end  88  and tip end  90 . In alternative embodiments, outer wall  94  extends to any suitable extent that enables component  80  to function for its intended purpose. Outer wall  94  is formed from component material  78 . 
     In addition, in certain embodiments, component  80  includes an inner wall  96 . Inner wall  96  is positioned interiorly to outer wall  94 , and the at least one internal void  100  includes at least one plenum  110  that is at least partially defined by inner wall  96  and interior thereto. In the exemplary embodiment, each plenum  110  extends from root end  88  to proximate tip end  90 . In alternative embodiments, each plenum  110  extends within component  80  in any suitable fashion, and to any suitable extent, that enables component  80  to be formed as described herein. In the exemplary embodiment, the at least one plenum  110  includes a plurality of plenums  110 , each defined by inner wall  96  and at least one partition wall  104  that extends between pressure side  74  and suction side  76 . In alternative embodiments, the at least one internal void  100  includes any suitable number of plenums  110  defined in any suitable fashion. Inner wall  96  is formed from component material  78 . 
     Moreover, in some embodiments, at least a portion of inner wall  96  extends circumferentially and longitudinally adjacent at least a portion of outer wall  94  and is separated therefrom by an offset distance  98 , such that the at least one internal void  100  also includes at least one chamber  112  defined between inner wall  96  and outer wall  94 . In the exemplary embodiment, the at least one chamber  112  includes a plurality of chambers  112  each defined by outer wall  94 , inner wall  96 , and at least one partition wall  104 . In alternative embodiments, the at least one chamber  112  includes any suitable number of chambers  112  defined in any suitable fashion. In the exemplary embodiment, inner wall  96  includes a plurality of apertures  102  defined therein and extending therethrough, such that each chamber  112  is in flow communication with at least one plenum  110 . 
     In the exemplary embodiment, offset distance  98  is selected to facilitate effective impingement cooling of outer wall  94  by cooling fluid supplied through plenums  110  and emitted through apertures  102  defined in inner wall  96 . For example, but not by way of limitation, offset distance  98  varies circumferentially and/or longitudinally along component  80  to facilitate local cooling requirements along respective portions of outer wall  94 . In alternative embodiments, component  80  is not configured for impingement cooling, and offset distance  98  is selected in any suitable fashion that enables component  80  to function as described herein. 
     In certain embodiments, the at least one internal void  100  further includes at least one return channel  114  at least partially defined by inner wall  96 . Each return channel  114  is in flow communication with at least one chamber  112 , such that each return channel  114  provides a return fluid flow path for fluid used for impingement cooling of outer wall  94 . In the exemplary embodiment, each return channel  114  extends from root end  88  to proximate tip end  90 . In alternative embodiments, each return channel  114  extends within component  80  in any suitable fashion, and to any suitable extent, that enables component  80  to be formed as described herein. In the exemplary embodiment, the at least one return channel  114  includes a plurality of return channels  114 , each defined by inner wall  96  adjacent one of chambers  112 . In alternative embodiments, the at least one return channel  114  includes any suitable number of return channels  114  defined in any suitable fashion. 
     For example, in some embodiments, cooling fluid is supplied to plenums  110  through root end  88  of component  80 . As the cooling fluid flows generally towards tip end  90 , portions of the cooling fluid are forced through apertures  102  into chambers  112  and impinge upon outer wall  94 . The used cooling fluid then flows into return channels  114  and flows generally toward root end  88  and out of component  80 . In some such embodiments, the arrangement of the at least one plenum  110 , the at least one chamber  112 , and the at least one return channel  114  forms a portion of a cooling circuit of rotary machine  10 , such that used cooling fluid is returned to a working fluid flow through rotary machine  10  upstream of combustor section  16  (shown in  FIG. 1 ). Although impingement flow through plenums  110  and chambers  112  and return flow through channels  114  is described in terms of embodiments in which component  80  is rotor blade  70  and/or stator vane  72 , it should be understood that this disclosure contemplates a cooling circuit  106  of plenums  110 , chambers  112 , and return channels  114  for any suitable component  80  of rotary machine  10 , and additionally for any suitable component  80  for any other application suitable for closed circuit fluid flow through a component. Such embodiments provide an improved operating efficiency for rotary machine  10  as compared to cooling systems that exhaust used cooling fluid directly from component  80  into the working fluid within turbine section  18 . 
     In alternative embodiments, the at least one internal void  100  does not include return channels  114 . For example, but not by way of limitation, outer wall  94  includes openings extending therethrough (not shown), and the cooling fluid is exhausted into the working fluid through the outer wall openings to facilitate film cooling of exterior surface  92 . In other alternative embodiments, component  80  includes both return channels  114  and openings (not shown) extending through outer wall  94 , a first portion of the cooling fluid is returned to a working fluid flow through rotary machine  10  upstream of combustor section  16  (shown in  FIG. 1 ), and a second portion of the cooling fluid is exhausted into the working fluid through the outer wall openings to facilitate film cooling of exterior surface  92 . 
     Although the at least one internal void  100  is illustrated as including plenums  110 , chambers  112 , and return channels  114  for use in cooling component  80  that is one of rotor blades  70  or stator vanes  72 , it should be understood that in alternative embodiments, component  80  is any suitable component for any suitable application, and includes any suitable number, type, and arrangement of internal voids  100  that enable component  80  to function for its intended purpose. 
     In some embodiments, apertures  102  each have a substantially circular cross-section. In alternative embodiments, apertures  102  each have a substantially ovoid cross-section. In other alternative embodiments, apertures  102  each have any suitable shape that enables apertures  102  to function as described herein. 
       FIG. 4  is a schematic exploded perspective view of a multiple component core assembly  400  defining at least a portion of cooling circuit  106  of component  80  (shown in  FIGS. 3 and 4 ).  FIG. 5  is a perspective view of multiple component core assembly  400  coupled together by a plurality of core connection components  500 . In the exemplary embodiment, component  80  (shown in  FIG. 2 ), in the form of rotor blade  70 , or alternatively stator vane  72 , is formed using an investment casting process, for example and without limitation, a lost wax investment casting process. Multiple component core assembly  400  is fabricated from a plurality of individual core components  401 . For example, in the exemplary embodiment, the individual core components  401  include a leading edge core component  402 , intermediate core components  404 ,  406 ,  408 , and  410 , and a trailing edge core component  412 . 
     In the exemplary embodiment, core components  402 ,  404 ,  406 ,  408 ,  410 , and  412  include various protrusions, for example protrusions  414  formed on leading edge core component  402  and trailing edge core component  412  that, when a casting process for forming component  80  is completed, define the plurality of apertures  102 , as shown in  FIG. 3 . 
     In the exemplary embodiment, individual core components  401  are individually shaped as required in accordance with a net shape of component  80  and define respective shapes and structures conforming to portions of cooling circuit  106  of component  80 , for example, plenums  110 , chambers  112 , and return channels  114 . Thus, when the casting process for forming component  80  is completed, the voids remaining after individual core components  401  are removed define cooling circuit  106  of component  80 . 
     In the exemplary embodiment, multiple component core assembly  400 , i.e., individual core components  401 , is formed from a core material  416 . In the exemplary embodiment, core material  416  is a refractory ceramic material selected to withstand a high temperature environment associated with a molten or fluid state of component material  78  used to form component  80 . For example and without limitation, core material  416  includes at least one of silica, alumina, and mullite. In addition, in the exemplary embodiment, core material  416  is selectively removable from component  80  to form the at least one internal void  100 . For example, but not by way of limitation, core material  416  is removable from component  80  by a suitable process that does not substantially degrade component material  78 , such as, but not limited to, a suitable chemical leaching process. In certain embodiments, core material  416  is selected based on a compatibility with, and/or a removability from, component material  78 . 
     Additionally or alternatively, core material  416  is selected based on a compatibility with a connection component material  502 . For example, in some such embodiments, core material  416  is selected to have a thermal expansion coefficient substantially similar to a thermal expansion coefficient of connection component material  502 , such that during heating of core components  402 ,  404 ,  406 ,  408 ,  410 , and  412  or multiple component core assembly  400 , the core components or core assembly and core connection component  500  expand at the same rate, thereby facilitating reducing stresses, cracking, and/or other damaging of the core components or core assembly due to mismatched thermal expansion. In alternative embodiments, core material  416  is any suitable material that enables component  80  to be formed as described herein. 
     In the exemplary embodiment, each of core components  402 ,  404 ,  406 ,  408 ,  410 , and  412 , and thus multiple component core assembly  400 , is formed and positioned in any suitable fashion that enables multiple component core assembly  400  to function as described herein. For example, but not by way of limitation, core material  416  is injected as a slurry into a suitable master core die (not shown) corresponding to a respective core component  402 ,  404 ,  406 ,  408 ,  410 , and  412 . Core material  416  is dried and fired at an elevated temperature in a separate core-forming process to form core components  402 ,  404 ,  406 ,  408 ,  410 , and  412  separate from one another. In alternative embodiments, core components  402 ,  404 ,  406 ,  408 ,  410 , and  412  are formed, for example, using a poured core molding process, a slip-cast molding process, or any other core forming process that enables core components  402 ,  404 ,  406 ,  408 ,  410 , and  412  to be formed and function as described herein. 
     As illustrated in  FIG. 5 , individual core components  401  are stacked and coupled together to form a unitary multiple component core assembly  400 . For example, core components  402 ,  404 ,  406 ,  408 ,  410 , and  412  can be manually assembled using a suitable fixture or assembled by a suitable automated process. In the exemplary embodiment, one or more core connection components  500  are used to couple individual core components  401  to each other and/or couple various portions of individual core components  401  together to form the respective individual core component. For example, each individual core component  401  includes at least one coupling portion  430  configured to be received within a corresponding connection component  500 . Each connection component  500  is configured to position at least one individual core component  401  with respect to another individual core component  401  when the respective coupling portions  430  are received therein. Alternatively, each connection component  500  is configured to position the at least one individual core component  401  with respect to another individual core component  401  in any suitable fashion. 
     In the exemplary embodiment, core connection component  500  is formed from a connection component material  502  selected to be at least partially absorbable by molten or fluid component material  78  used to form component  80 . For example, in one embodiment, component material  78  is an alloy, and connection component material  502  is at least one constituent material of the alloy. 
     In the exemplary embodiment, connection component material  502  is substantially nickel and component  80  is formed from a nickel-based superalloy, such that connection component material  502  is compatible with component material  78  when the material in its molten state is introduced into a mold  702  (shown in  FIG. 7 ). In alternative embodiments, component material  78  is any suitable alloy, and connection component material  502  is at least one material that is compatible with the molten alloy. For example, in some embodiments, component material  78  is a cobalt-based superalloy, and connection component material  502  is substantially cobalt. For another example, component material  78  is an iron-based alloy, and connection component material  502  is substantially iron. For another example, component material  78  is a titanium-based alloy, and connection component material  502  is substantially titanium. 
     In certain embodiments, connection component material  502  is substantially absorbed by component material  78  when the component material  78  in its molten or fluid state is introduced into mold  702 . For example, in some such embodiments, connection component material  502  is substantially absorbed by component material  78  such that no discrete boundary delineates connection component material  502  from component material  78  after the material is cooled. Moreover, in some such embodiments, connection component material  502  is substantially absorbed such that, after component material  78  is cooled, connection component material  502  is substantially uniformly distributed within component material  78 . For example, a concentration of connection component material  502  proximate a location of connection component material  502  prior to casting component  80  is not detectably higher than a concentration of connection component material  502  at other locations within component  80 . For example and without limitation, connection component material  502  is nickel and component material  78  is a nickel-based superalloy, and no detectable higher nickel concentration remains after component material  78  is cooled, resulting in a distribution of nickel that is substantially uniform throughout the nickel-based superalloy of formed component  80 . 
     In alternative embodiments, connection component material  502  is other than substantially absorbed by component material  78 . For example, in some embodiments, connection component material  502  is partially absorbed by component material  78 , such that after component material  78  is cooled, connection component material  502  is other than substantially uniformly distributed within component material  78 . For example, a concentration of connection component material  502  proximate a location of connection component material  502  prior to casting component  80  is detectably higher than a concentration of connection component material  502  at other locations within component  80 . In some such embodiments, connection component material  502  is insubstantially absorbed, that is, at most only slightly absorbed, by component material  78  such that a discrete boundary delineates connection component material  502  from component material  78  after component material  78  is cooled. Additionally or alternatively, in some such embodiments, connection component material  502  is insubstantially absorbed by component material  78  such that at least a portion of connection component material  502  remains intact after component material  78  is cooled. For another example, connection component material  502  melts and collects at the bottom of mold  702  during a pre-heat process prior to casting or molding component  80 , yielding a detectably high concentration of connection component material  502  in a portion of component  80  formed proximate the bottom of mold  702 . 
       FIG. 6  is a schematic sectional view of an exemplary core split line  602  of multiple component core assembly  400 , taken along line  6 - 6  in  FIG. 5 . As shown in  FIG. 6  for example, coupling portions  430  of core components  402  and  404  are received within a respective connection component  500  and coupled together along core split line  602 . While core split line  602  is shown as a standard butt joint, it is contemplated that the connection between respective individual core components  401  can be any type of joint, for example and without limitation, a dovetail joint, a half-lap joint, a tongue and groove joint, and any other suitable joint that enables multiple component core assembly  400  to be formed as described herein. 
     In the exemplary embodiment, core connection component  500  is a mechanical connector. The term “mechanical connector,” as used herein, encompasses any structural and/or physical component for mechanically coupling two components together, such as a sheath, stamp, pin, or screw. For example, in the embodiment illustrated in  FIG. 6 , core connection component  500  is embodied as a sleeve  501  shaped to receive coupling portions  430  of components  402  and  404  therein, such that core components  402  and  404  are coupled together along core split line  602 . 
     For another example,  FIG. 9  is a schematic view of an alternative exemplary core split line  602  of multiple component core assembly  400  in which coupling portions  430  of adjacent core components  401  are coupled together using core connection component  500  embodied as a sheath  901 . More specifically, coupling portions  430  are shaped to define adjacent protrusions, and sheath  901  is shaped to receive the protrusions therein, such that core components  401  are coupled together along core split line  602 . 
     For another example,  FIG. 10  is a schematic view of an alternative exemplary core split line  602  of multiple component core assembly  400  in which coupling portions  430  of adjacent core components  401  are coupled together using core connection component  500  embodied as a stamp  1001 . More specifically, stamp  1001  is configured to be mechanically stamped onto each of coupling portions  430 , such that core components  401  are coupled together along core split line  602 . 
     For another example,  FIG. 11  is a schematic view of an alternative exemplary core split line  602  of multiple component core assembly  400  in which coupling portions  430  of adjacent core components  401  are coupled together using core connection component  500  embodied as a pin  1101 . More specifically, pin  1101  is configured to be received within each of coupling portions  430 , such that core components  401  are coupled together along core split line  602 . 
     For another example,  FIG. 12  is a schematic view of an alternative exemplary core split line  602  of multiple component core assembly  400  in which coupling portions  430  of adjacent core components  401  are coupled together using core connection component  500  embodied as a screw  1201 . More specifically, screw  1201  is configured to be received within each of coupling portions  430 , such that core components  401  are coupled together along core split line  602 . 
     In alternative embodiments, core connection component  500  is any other connector type that enables core connection component  500  to position individual core components  401  with respect to each other, as described herein. 
     In certain embodiments, a chemical connector  1301  is used in addition to core connection component  500  to further secure individual core components  401  along core split line  602 . The term “chemical connector” as used herein is a substance that bonds adjacent surfaces of two components together, such as an adhesive or braze. For example,  FIG. 13  is a schematic view of an alternative exemplary core split line  602  of multiple component core assembly  400  in which coupling portions  430  of adjacent core components  401  are coupled together using core connection component  500  embodied as sleeve  501 , as shown in  FIG. 6 , and also using chemical connector  1301  embodied as an adhesive. Alternatively, chemical connector  1301  is any suitable chemical connector. In the exemplary embodiment, chemical connector  1301  is formed from a material selected to be compatible with molten or fluid component material  78  used to form component  80 . In some embodiments, chemical connector  1301  facilitates stabilizing a position of core components  401  with respect to each other, such as during a process of forming mold  702  (shown in  FIG. 7 ). Alternatively, chemical connector  1301  is not used at core split line  602 . 
     In certain embodiments, core connection component  500  structurally reinforces multiple component core assembly  400 , and in particular, connections along the core split lines, for example core split line  602  between core component  402  and core component  404 . Thus core connection component  500  facilitates reducing potential problems that would be associated with production, handling, and use of an unreinforced multiple component core assembly  400  in some embodiments. 
     For example, in certain embodiments, multiple component core assembly  400  is a relatively brittle ceramic material subject to a relatively high risk of fracture, cracking, and/or other damage due, in part, to the intricately-shaped features that define the voids and internal passages of component  80 . Thus, in some such embodiments, forming and assembling separate individual core components  401 , such as core components  402 ,  404 ,  406 ,  408 ,  410 , and  412 , using core connection components  500  presents a much lower risk of damage to multiple component core assembly  400 , as compared to using a single core component corresponding to multiple component core assembly  400 . Similarly, in some such embodiments, forming mold  702  (shown in  FIG. 7 ) around multiple component core assembly  400 , such as by repeated investment of multiple component core assembly  400  in a slurry of mold material, presents a lower risk of damage to multiple component core assembly  400 , as compared to using a single core component corresponding to multiple component core assembly  400 . Thus, in certain embodiments, use of multiple component core assembly  400  with core connection components  500  presents a lower risk of failure to produce an acceptable component  80 , as compared to forming component  80  using a single core component corresponding to multiple component core assembly  400 . In addition, because connection component material  502  is absorbable by component material  78  when component  80  is cast, the use of connection component  500  reduces a time and complexity of the component casting process as compared to, for example, using pins that must be removed prior to casting to position individual core components  401  with respect to each other and/or mold  702 . 
     In certain embodiments, core components  401  are positioned with respect to each other in a preselected orientation, such as using external fixtures (not shown), and a preformed core connection component  500  is coupled to at least two of the core components  401  to form multiple component core assembly  400 . In other embodiments, core components  401  are positioned with respect to each other in a preselected orientation, such as using external fixtures (not shown), and core connection component  500  is formed in place around at least two of the core components  401 , such as by using a suitable deposition process. For example, with reference again to  FIG. 6 , core connection component  500  is formed on at least a portion of the surfaces of coupling portions  430  of two adjacent core components  401  by a plating process, such that connection component material  502  is deposited on coupling portions  430  until a selected thickness of core connection component  500  is achieved. Application of connection component material  502  to other surfaces of core components  401  is inhibited using any suitable method, for example by masking of such other surfaces. 
     For example, connection component material  502  is a metal, and is deposited on coupling portions  430  in a suitable metal plating process. In some such embodiments, connection component material  502  is deposited on coupling portions  430  in an electroless plating process. Additionally or alternatively, connection component material  502  is deposited on coupling portions  430  in an electroplating process. In alternative embodiments, connection component material  502  is any suitable material, and core connection component  500  is formed on coupling portions  430  by any suitable plating process that enables core connection component  500  to function as described herein. 
     In some such embodiments, connection component material  502  includes a plurality of materials disposed on coupling portions  430  in successive layers. For example, coupling portions  430  are formed from a ceramic material, an initial layer of connection component material  502  is a first metal alloy selected to facilitate electroless plating deposition onto coupling portions  430 , and a subsequent layer of connection component material  502  is a second metal alloy selected to facilitate electroplating to the prior layer of connection component material  502 . In some such embodiments, the first and second metal alloys are alloys of nickel. In other embodiments, coupling portions  430  are formed from any suitable material, connection component material  502  is any suitable plurality of materials, and core connection component  500  is formed on coupling portions  430  by any suitable process that enables core connection component  500  to function as described herein. 
       FIG. 7  is a schematic view of an exemplary mold assembly  700  that includes multiple component core assembly  400  and is used to form component  80  shown in  FIG. 1 . In the exemplary embodiment, mold assembly  700  includes multiple component core assembly  400  positioned with respect to mold  702 . An interior wall  706  of mold  702  defines a mold cavity  708  within mold  702 , and multiple component core assembly  400  is at least partially received in mold cavity  708 . More specifically, interior wall  706  defines a shape corresponding to an exterior shape of component  80 , such that multiple component core assembly  400 , which has a shape corresponding to cooling circuit  106  of component  80 , is positioned in a spaced relationship with interior wall  706 . 
     In the exemplary embodiment, mold  702  is formed from a mold material  710 . For example in the exemplary embodiment, mold material  710  is a refractory ceramic material selected to withstand a high temperature environment associated with the molten or fluid state of component material  78 . In alternative embodiments, mold material  710  is any suitable material that enables component  80  to be formed as described herein. Moreover, in the exemplary embodiment, mold  702  is formed by a suitable investment process. 
     For example and without limitation, component  80  is formed using a lost wax investment casting process. Multiple component core assembly  400  is encased in pattern material, such as a wax  704 , that is shaped to conform to a desired configuration of component  80 . Wax  704 , including multiple component core assembly  400  at least partially encased therein, is then repeatedly dipped into a slurry of mold material  710 , which is allowed to harden to create a shell  712  of mold material  710 , and shell  712  is fired to form mold  702 . In alternative embodiments, mold  702  is formed by any suitable method that enables mold  702  to function as described herein. In the exemplary embodiment, during firing of shell  712 , wax  704  is melted out of shell  712 , such that the remaining mold  702  includes multiple component core assembly  400 , external ceramic shell  712 , and mold cavity  708 , which was previously filled with wax  704 , defined therebetween. Mold cavity  708  is then filled with molten component material  78  to form component  80 . In some embodiments, connection component material  502  of core connection component  500  is substantially absorbed by the molten component material  78  used to form component  80 , while in other embodiments, for example, core connection component  500  remains at least partially intact adjacent component material  78  within mold cavity  708 , as described herein. 
     In the exemplary embodiment, after component material  78  cools and solidifies in mold cavity  708 , shell  712  is removed to expose component material  78  that has taken the shape of mold cavity  708 , i.e., component  80 . Multiple component core assembly  400  is removed from component  80  to form the cooling circuit  106  therein. For example, but not by way of limitation, core material  416  is removed from component  80  using a chemical leaching process. 
     Moreover, after removal of core material  416  from component  80 , there may be small portions of component material  78  extending into cooling circuit  106 , i.e., plenums  110 , chambers  112 , and return channels  114  of component  80 , at locations corresponding to core split lines  602  defined between core components  402 ,  404 ,  406 ,  408 ,  410 , and  412 , for example. These small portions of component material  78 , or casting bridges, are removed from cooling circuit  106  using any tooling processes, for example and without limitation, drilling, wire electrical discharge machining (EDM), electrochemical machining, milling, and any other tooling process that enables excess component material  78  to be removed from cooling circuit  106  as described herein. 
     An exemplary method  800  of forming a component, such as component  80 , is illustrated in a flow diagram in  FIG. 8 . With reference also to  FIGS. 1-7 , exemplary method  800  includes separately forming  802  at least two individual core components  401 , for example, one or more of core components  402 ,  404 ,  406 ,  408 ,  410 , and  412 , using any core forming process, such as injecting a slurry of a core material into a respective master core die. Additionally, method  800  further includes coupling  804  at least two core components, e.g. core components  402  and  404 , together to form multiple component core assembly  400 . For example, the step of coupling  804  at least two core components together further includes coupling  806  core connection component  500  to each of the at least two core components using a mechanical connection, as described herein. 
     Furthermore, method  800  includes positioning  807  multiple component core assembly  400  with respect to mold cavity  708  defined in a mold  702 . In addition, method  800  includes encasing  808  multiple component core assembly  400  in a pattern material, such as wax  704 , where the pattern material is shaped to conform to a desired configuration of component  80 , or at least portions thereof. 
     In the exemplary embodiment, method  800  includes forming  810  a shell  712  around wax  704 , including multiple component core assembly  400 , by an investment process, as described herein. For example, the step of forming  810  shell  712  includes repeatedly dipping  812  wax  704  into a slurry of mold material  710 , which is allowed to harden to create the shell  712  of mold material  710 . In addition, method  800  includes firing  814  shell  712  to form mold  702 . 
     Method  800  further includes removing  816  wax  704  from mold  702 . In one embodiment of method  800 , removing  816  wax  704  includes melting  818  wax  704  out of shell  712  during firing of shell  712 , so that the remaining mold  702  includes multiple component core assembly  400 , external ceramic shell  712 , and mold cavity  708 . 
     In addition, method  800  includes introducing  820  a component material, such as component material  78  used to form component  80 , in a molten or fluid state into mold cavity  708  defined in mold assembly  700 , such that core connection component  500  is at least partially absorbed by component material  78 , as described herein. Mold assembly  700  includes multiple component core assembly  400  positioned with respect to mold  702 , interior wall  706 , and mold cavity  708  defined by interior wall  706  which is left behind after removal of wax  704 . Multiple component core assembly  400  is coupled in a spaced relationship with respect to interior wall  706 . 
     Method  800  also includes cooling  822  component material  78  used to form component  80 . Interior wall  706  and multiple component core assembly  400  cooperate to define the shape of component  80 . 
     In addition, method  800  includes removing  824  multiple component core assembly  400  from component  80  to form cooling circuit  106  therein. For example, but not by way of limitation, core material  416  is removed from component  80  using a chemical leaching process. Additionally, in some embodiments of method  800 , the method includes removing  826  small portions of component material  78 , such as casting bridges corresponding to the core split line, from cooling circuit  106  of component  80  left behind after the removal of multiple component core assembly  400 . The casting bridges may be removed using any tooling processes, for example and without limitation, drilling, wire electrical discharge machining (EDM), electrochemical machining, milling, and any other tooling process that enables excess component material  78  to be removed from cooling circuit  106  as described herein. 
     The above-described embodiments of multiple component core assemblies, mold assemblies, and methods enable fabricating hot gas path components or other suitable components with improved precision and repeatability as compared to at least some known mold assemblies and methods. Specifically, the multiple component core assembly includes at least two individual core components coupled together using at least one core connection component. The core connection component enables the complete core to be formed from smaller individual core portions that are less susceptible to damage than a unitary complete core, and protects the multiple component core assembly from damage during forming and firing of the mold. Also specifically, the use of the core connection component in forming the multiple component core assembly facilitates reducing a time and cost of preparing the mold assembly for prototyping or production operations, for example by reducing or eliminating a need for locating pins in the mold assembly that must be removed prior to casting the component. In some cases, the above-described embodiments enable formation of components having structures that cannot be precisely and/or repeatably formed using other known mold assemblies and methods. 
     An exemplary technical effect of the methods, systems, and apparatus described herein includes at least one of: (a) reducing or eliminating fragility problems associated with forming, handling, transport, and/or storage of a core used in forming a component; (b) improving precision and repeatability of formation of components having intricate internal voids and structures; and (c) enabling increased speed in design iterations by rapidly forming intricate cores and casting components having intricate internal voids and structures. 
     Exemplary embodiments of multiple component core assemblies and methods including such core assemblies are described above in detail. The multiple component cores assemblies, and methods using such core assemblies, are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the exemplary embodiments can be implemented and utilized in connection with many other applications that are currently configured to use investment casting mold assemblies. 
     Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing. 
     This written description uses examples to disclose the embodiments, including the best mode, and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.