Patent Description:
MTR's exist in titanium alloys, nickel alloys, or the like. A MTR may contain hexagonal α-phase crystallites aligned, mostly, in the same or close crystallographic orientation in a region far greater than a typical α grain size. Microstructure is a fine structure of material. The presence of MTR's may reduce service life of various components. For example, the existence of MTR was linked to dwell fatigue susceptibility, which may cause early failure in titanium-based aero-engine components. Typical methods for MTR characterization are destructive to the component.

<CIT> discloses a technique and device being utilized to determine a characteristic of a crystallographic texture of a sample based on a detected ultrasonic waveform representative of a reflected ultrasonic waveform that propagated through the sample.

AIP Conference proceedings discloses the ultrasonic scattering from microtexture regions within a Ti-6Al-4V titanium alloy being analyzed for mode-converted shear wave interactions.

<NPL> Microscopy and Microanalysis describes ultrasonic inspection being routinely performed on many critical aerospace components at various stages of manufacture.

<NPL> Journal of Nondestructive evaluation describes diffusion binds offering several advantages over alternative welding methods.

<CIT> discloses a method for measuring texture of metal plates or sheets using non-destructive ultrasonic investigation.

<NPL> describes using ultrasonic attenuation measurements of the component in pulse-echo imaging mode.

<CIT> discloses the identification and quantification of microtextured regions in orientation datasets provided through the use of microstructure informatics based on n-point correlation functions, dimensionality reduction techniques, and a computer algebra system.

<CIT> discloses a system for the x-ray topography analysis of a sample, and a method for the characterization of microtextured regions in the sample.

According to the invention, a method is provided as recited in claim <NUM>.

Further, optional features are provided in each of claims <NUM> to <NUM>.

The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in, and constitute a part of, this specification, illustrate various embodiments, and together with the description, serve to explain the principles of the disclosure.

The detailed description of various embodiments herein makes reference to the accompanying drawings, which show various embodiments by way of illustration. While these various embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that logical, chemical, electrical, and mechanical changes may be made without departing from the scope of the claims.

For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Also, any reference to attached, fixed, connected, or the like may include permanent, removable, temporary, partial, full, and/or any other possible attachment option.

For example, in the context of the present disclosure, methods, systems, and articles may find particular use in connection with gas turbine engines. However, various aspects of the disclosed embodiments may be adapted for optimized performance in a variety of engines or other applications. As such, numerous applications of the present disclosure may be realized.

Ultrasonic waves propagating in polycrystals create backscattered noise due to variations of physical properties in microstructures. The strength of backscattered noise is related to wavelength, beam properties, and microstructure properties, etc. In case of titanium forgings, typical grain sizes are around <NUM> microns, while MTR sizes are in order of a few hundreds to a few thousands microns. For an ultrasonic transducer with a center frequency of <NUM>, its wavelength is about <NUM> in a longitudinal mode, and is about <NUM> in a transverse wave mode, respectively. As these wavelengths are far greater the grain sizes but in comparable with MTR sizes, it is expected that MTR's are far more significant contributors to backscattered noise than typical grains under this working frequency. The selection of ultrasonic working frequency is dependent on MTR sizes of interest, geometry, material properties, and so on. The strength of backscattered noise is also significantly influenced by the angle between the orientation of a microstructural feature and the propagating direction of ultrasonic waves. For instance, an ellipsoidal scatterer generates least amount of backscattered noise when its elongation direction is parallel with the wave propagation direction. In contrast, a same sized ellipsoidal scatterer could generate far greater amount of backscattered noise when its elongation direction is normal to the wave propagation direction. Consequently, it is ideal to choose the incidence angle of ultrasonic waves to be normal to the grain flow line direction of the region of interests. For a component of complex geometry, it is often wise to segment the region of interests based on its primary grain flow line orientation and select the corresponding incident angles and gating parameters for each individual region. Generally, efforts shall be made to control relevant factors in the inspection process to increase comparability among regions of interests. It is expected that sensitivity of MTR evaluation increases when more relevant factors are controlled. For example, more sensitive comparisons may be achieved among areas with same or close geometric features, sam flow line orientations and inspected with same inspection parameters.

In a typical amplitude C-scan image, a peak amplitude is recorded at each scanning position, whereas the peak amplitude corresponding to the maximum (peak) value of backscattered noise within a pre-defined (time) gate recorded at the associated scanning position. As a whole, a C-scan image is a two-dimensional matrix of peak amplitudes of backscattered noises. Consequently, a number of statistical indicators can be derived from a C-scan image, either treated as a one-dimensional sequence, or a two-dimensional matrix. Some statistical estimators may be derived from the corresponding spatial frequency spectrum, which is a two-dimensional Fourier transform of the original image.

Referring now to <FIG>, in accordance with various embodiments, a system <NUM> of MTR characterization of a component <NUM> is illustrated, in accordance with various embodiments. The system comprises a tank <NUM>, a component <NUM>, a transducer <NUM>, and a controller <NUM>. The component <NUM> may comprise a metal, metal alloy, or any other suitable material. The component <NUM> may be a stainless steel alloy, a nickel alloy, a titanium alloy, an aluminum alloy, or the like. In various embodiments, the tank <NUM> may be filled with a fluid <NUM>, such as water or the like. The component <NUM> is disposed in the tank <NUM>. The component <NUM> may be disposed on supports disposed between the component <NUM> and a surface of the tank <NUM>. The transducer <NUM> may be a single-element immersion ultrasonic transducer or a phased array transducer containing a number of elements. The transducer <NUM> may also be disposed in the tank <NUM> and electrically coupled to the controller <NUM>.

The system <NUM> includes the controller <NUM> in electronic communication with the transducer <NUM>. In various embodiments, controller <NUM> may contain a pulser/receiver, which can drive the transducer <NUM> to transmit and receive ultrasonic pulses. In various embodiments, controller <NUM> may also contain a high-speed analog-to-digital converter, which can convert received analog ultrasonic signals into digital signals for recording and processing. In various embodiments, controller <NUM> may contain a motion control module, which can position the transducer <NUM> at a desired scanning position and perform automated inspection of a component <NUM> following a pre-defined scanning surface. In various embodiments, controller <NUM> may contain a software tool to perform various signal/image acquisition, filtering, display and storage functionalities. In various embodiments, controller <NUM> may contain a software interface, which enables user adjustment of inspection parameters of all relevant subsystems mentioned previously. In various embodiments, controller <NUM> may contain a PC to host all software tools as well as hardware components. In various embodiments, controller <NUM> may be configured as a central network element or hub to access various systems and components of system <NUM>. Controller <NUM> may comprise a network, computer-based system, and/or software components configured to provide an access point to various systems and components of system <NUM>.

In various embodiments, controller <NUM> may comprise a processor. In various embodiments, controller <NUM> may be implemented in a single processor. In various embodiments, controller <NUM> may be implemented as and may include one or more processors and/or one or more tangible, non-transitory memories and be capable of implementing logic. Each processor can be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. Controller <NUM> may comprise a processor configured to implement various logical operations in response to execution of instructions, for example, instructions stored on a non-transitory, tangible, computer-readable medium configured to communicate with controller <NUM>.

System program instructions and/or controller instructions may be loaded onto a non-transitory, tangible computer-readable medium having instructions stored thereon that, in response to execution by a controller, cause the controller to perform various operations. The term "non-transitory" is to be understood to remove only propagating transitory signals per se from the claim scope and does not relinquish rights to all standard computer-readable media that are not only propagating transitory signals per se.

In various embodiments, controller <NUM> may be in electronic communication with the transducer <NUM>. The transducer <NUM> may comprise an ultrasonic single-element transducer, a phased array transducer or the like. For example, the transducer <NUM> may be configured to convert a broad band excitation signal into an ultrasonic wave. The transducer <NUM> may be configured to produce an ultrasonic wave <NUM> into within the tank <NUM> filled with the fluid <NUM> and receive a return signal of the ultrasonic wave <NUM>. The ultrasonic wave <NUM> may propagate within the component <NUM>. For example, a first return signal <NUM> may be produced on a front surface <NUM> of the component <NUM>. Similarly, a second return signal <NUM> may be produced on a back surface <NUM> of the component <NUM>. If there is a defect <NUM> in the component, a third return signal <NUM> may be produced from the defect <NUM> of the component <NUM>.

In various embodiments, the controller <NUM> may be programmed to control the position and excitation parameters of transducer <NUM>. Although shown as controlling the transducer, in various embodiments, a controller <NUM> may be coupled a robot/servomotor that is coupled to the component <NUM> and programmed to control the position of the component <NUM> while the transducer <NUM> remains stationary. In various embodiments, the transducer <NUM> may be moved automatically during operation.

The transducer <NUM> is configured to receive ultrasonic backscattered noise associated with the microstructure variations within the component <NUM>. "Backscattered noise," as disclosed herein, contains ultrasonic waves <NUM> reflected by microstructures in component <NUM> and received by the transducer <NUM>. The controller <NUM> may record the backscattered noise collected at each X-Y coordinates on a scanning surface of a sample of the component <NUM>. For example, with brief reference to <FIG>, a C-Scan of a baseline sample (<FIG>) and a low noise sample (<FIG>) of a component <NUM> is illustrated. The baseline sample and the low noise sample are same component fabricated with different heat treatment processes, respectively. Consequently, the low noise sample has smaller MTR sizes as compared to that of the baseline sample. A "C-Scan," as referred to herein, is data collected from an ultrasonic inspection that is plotted on a top view of the component surface under test. A C-scan image allows pseudo color to represent the peak amplitudes within a time or depth gate as a function of transducer position. The two-dimensional images can be generated on flat, or curved, parts by tracking data to an X-Y position on a scanning surface. In various embodiments, the peak amplitude of the baseline sample (<FIG>) and the low noise sample (<FIG>) are recorded. As shown, the backscattered noise of the low noise sample (<FIG>) has a relatively tight amplitude distribution over the sample (i.e., the amplitude of backscattered noise has a smaller standard deviation), in comparison with backscattered noise of the baseline sample (<FIG>). This backscattered noise is quantified and used to characterize MTR content of a component <NUM>.

From the data collected in the C-Scan, a plot of peak amplitudes for a given sample, or a selected zone within the sample, in descending order from largest to smallest may be established. The peak amplitudes may correspond to backscattered noise from MTRs within the sample, as well as other microstructural features. A peak factor is defined by the following equation: <MAT>.

A mean of the peak factors may be calculated over a pre-determined sample size. For example, a sample size may be <NUM>-<NUM> peak factors, <NUM>-<NUM>,<NUM> peak factors, or the like. Alternatively, a mean of the peak factors may be calculated over a qualified pool of samples. For example, all peak amplitudes greater than the sum of the mean peak amplitude plus two times of the standard deviation may be selected. The first <NUM>-<NUM> peak factors may be removed from the sample as potential outliers. Any number of outliers may be removed from the sample and be within the scope of this disclosure. The peak factor for a sample/region may be plotted vs. the sample index. For example, each amplitude in the sample/region may correspond to a respective peak factor. In various embodiments, in plotting the peak factor as a function of the sample index, two samples/regions may be compared to characterize MTR content. A lower peak factor may correspond to lower microtexture levels and/or greater service life of the sample and/or component, in combination with knowledge of other critical factors related to service life. For example, referring now to <FIG>, the peak factor vs. the number of peaks is plotted for the baseline sample (<FIG>), and the low noise sample (<FIG>), respectively. The peak factor of each peak is calculated of range R1, which is normalized. For example, when the range is from the <NUM>th largest peak to the <NUM>th largest peak, the number of peaks is plotted from <NUM> to <NUM>. From the plot shown in <FIG>, an average peak factor can be calculated over the range R1. The average peak factor can be utilized to characterize each sample (i.e., baseline sample (<FIG>) and low noise sample (<FIG>). As shown, the peak factor, and average peak factor, of the low noise sample (<FIG>) is lower over the entire range R1 compared to the baseline sample (<FIG>). As such, the low noise sample may be characterized as having lower microtexture levels and/or greater service life than the baseline sample (<FIG>). The peak factor is utilized as an indicator of a microtexture level of a given sample, component, or the like.

For example, peak factors may be plotted as an average peak factor over a first range (e.g., peaks <NUM>-<NUM>,<NUM>) vs average peak factor over a second range (e.g., peaks <NUM>-<NUM>) (i.e., <FIG>). In this regard, a microtexture level of samples may be compared. For example, with reference to <FIG>, peak factors of the baseline sample from <FIG>, the low noise sample from 2B, and a high noise sample are plotted over a first range (<NUM>-<NUM>,<NUM>) vs. a second range (<NUM>-<NUM>). The plot may provide visual indications of which samples (i.e., baseline, low noise, or high noise) have lower or higher microtexture levels. In various embodiments, the plot may provide visual indications of which region (i.e., a first region of the baseline compared to a second region of the baseline) has lower or higher microtexture levels. The microtexture levels may be utilized to determine which regions of a component may experience greater service life, which heat treatments provides greater service life for a given component, which components in a batch of components provide greater service life, and/or which components in a batch of components should be scrapped.

In various embodiments, not falling under the scope of the claims, an indicator of a microtexture level may comprise a standard deviation of peak amplitudes comparison. Despite efforts made to achieve similar amplitude range in each testing zone, some variations in amplitudes exist due to variations in incident wave strength, geometry, material properties and beam properties. Thus, peak amplitudes acquired from different samples/zones may be scaled to have same mean amplitude first to enable direct comparison with each other. The standard deviation of scaled peak amplitudes may be plotted as a standard deviation of a region (i.e., zone) vs. the region (i.e., zone) of the sample (i.e., <FIG>). In this regard, a microtexture level of samples may be compared. For example, with reference to <FIG>, standard deviations of the baseline sample from <FIG>, the low noise sample from 2B, and a high noise sample are plotted over various zones, or regions, of a sample. The plot may provide visual indications of which samples (i.e., baseline, low noise, or high noise) have lower (e.g., low noise) or higher (e.g., high noise) microtexture levels. In various embodiments, the plot may provide visual indications of which region (i.e., a first region of the baseline compared to a second region of the baseline) has lower or higher microtexture levels. The microtexture levels may be utilized to determine which regions of a component may experience greater service life, which heat treatments provides greater service life for a given component, which components in a batch of components provide greater service life, and/or which components in a batch of components should be scrapped.

In various embodiments, not falling under the scope of the claims, an indicator of a microtexture level may comprise a baseband bandwidth comparison. A C-scan amplitude image may be transformed to frequency domain utilizing a two-dimensional Fourier transform. Generally, most power in the frequency domain locates within the baseband, which is the band close to the zero frequency. The bandwidth of the baseband contains useful information of how backscattered noises are distributed spatially. Herein, a bandwidth is not limited to the common definition of a 6dB width, but may be a 10dB width, a <NUM> dB width, or like. Moreover, a bandwidth is defined as the longest width of the baseband, as a two-dimensional baseband may not be axis-symmetric, or its elongation direction may not aligned with either axis of the domain. Consequently, a baseband bandwidth defined with a first width (e.g., 20dB width) of the sample may be plotted vs. a baseband bandwidth defined with a second width (e.g., <NUM> dB width) of the sample (i.e., <FIG>). In this regard, a microtexture level of samples may be compared. For example, with reference to <FIG>, baseband bandwidth in a <NUM> dB sense of the baseline sample from <FIG>, the low noise sample from 2B, and a high noise sample are plotted against baseband bandwidth in a <NUM> dB sense of the sample. The plot may provide visual indications of which samples (i.e., baseline, low noise, or high noise) have lower (e.g., low noise) or higher (e.g., high noise) microtexture levels. In various embodiments, the plot may provide visual indications of which region (i.e., a first region of the baseline compared to a second region of the baseline) has lower or higher microtexture levels. The microtexture levels may be utilized to determine which regions of a component may experience greater service life, which heat treatments provides greater service life for a given component, which components in a batch of components provide greater service life, and/or which components in a batch of components should be scrapped.

In various embodiments, this disclosure may be applied to a gas turbine engine in an aircraft, and specifically, in a fan blade, or other rotor blade, of a gas turbine engine. Referring to <FIG>, a gas turbine engine <NUM> is illustrated according to various embodiments. The gas turbine engine <NUM> may generally comprise, in serial flow communication, a fan <NUM> through which ambient air is propelled, a compressor section <NUM> for pressurizing the air, a combustor <NUM> in which the compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases, and a turbine section <NUM> for extracting energy from the combustion gases. Axis of rotation <NUM> may define the forward-aft position of the gas turbine engine <NUM>. For example, the fan <NUM> may be referred to as forward of the turbine section <NUM> and the turbine section <NUM> may be referred to as aft of the fan <NUM>. As air flows from the fan <NUM> to the more aft components of the gas turbine engine <NUM>, the axis of rotation <NUM> may also generally define the direction of the air stream flow.

Referring to <FIG> and <FIG>, in accordance with various embodiments, a rotor <NUM> which may be used in the gas turbine engine <NUM> of <FIG>, or in any other adequate type of gas turbine engine, is illustrated. In the illustrated embodiment, the rotor <NUM> is a first stage of a high pressure compressor of the compressor section <NUM>. However, it is understood that the rotor can be any other rotor of the gas turbine engine <NUM>, including a turbine rotor, a fan rotor, and so on. The rotor <NUM> may comprise a rotor disk <NUM> which supports a circumferential array of regularly spaced blades <NUM>. The rotor disk <NUM> and the blades <NUM> may be, but are not necessarily, integrally molded (i.e., form a monolithic structure). The rotor disk <NUM> may include a hub <NUM> for engaging a central shaft. With combined reference to <FIG> and <FIG>, the system <NUM> may be utilized to determine which regions of a component (e.g., rotor <NUM>) may experience greater service life, which heat treatments provides greater service life for a given component (e.g., rotor <NUM>), which components in a batch of components (e.g., a batch of rotor <NUM>) provide greater service life, and/or which components in a batch of components (e.g., a batch of rotor <NUM>) should be scrapped. Although described with respect to rotor <NUM>, a microtexture analysis of any component is within the scope of this disclosure.

Referring now to <FIG>, a method <NUM> of determining a service life limiting region of a component is illustrated in accordance with various embodiments. The method comprises scanning a plurality of regions of a component (step <NUM>). The scanning may be performed in accordance with the system <NUM> from <FIG>. The component may comprise a rotor <NUM>, or any other gas-turbine engine component. The scanning is performed by an ultrasonic transducer. The method <NUM> further comprise calculating a microtexture level indicator for each region in the plurality of regions (step <NUM>).

The method <NUM> further comprises comparing the microtexture level indicator for each region in the plurality of regions of the component (step <NUM>). In this regard, the microtexture level indicator may be plotted providing a visual indication of the microtexture level indicator as a function of region. The method <NUM> further comprises characterize limiting region in the plurality of regions of the component (step <NUM>). In this regard, a region in the plurality of regions that includes the highest microtexture level indicator in the plurality of regions is characterized as a limiting region of the component. The limiting region of the component may correspond to a service life limiting region of the component. A "service life limiting region" as disclosed herein may correspond to a region of a component that is likely to limit the service life of the component based on its microtexture level. By characterizing a component in this manner, a design of a component may be modified to increase a service life of the component. In various embodiments, characterizing refers to assigning a service life limit to the life limiting region of the component, or the like.

Referring now to <FIG>, a method <NUM> of determining selecting components for use in production is illustrated, in accordance with various embodiments. The method comprises scanning a batch of components (step <NUM>). The scanning is performed in accordance with the system <NUM> from <FIG>. The component may comprise a rotor <NUM>, or any other gas-turbine engine component. The scanning may be performed by an ultrasonic transducer. The method <NUM> may further comprise calculating a microtexture level indicator for each component in the batch of components (step <NUM>). In various embodiments, a life limiting region from method <NUM> may be analyzed for each component in the batch of components.

The method <NUM> may further comprise comparing the microtexture level indicator for each component in the batch of components (step <NUM>). In this regard, the microtexture level indicator may be plotted providing a visual indication of the microtexture level indicator as a function of the batch of components. The method <NUM> may further comprise scrapping a portion of the components in the batch of components in response to the microtexture level indicator of the portion of the components exceeding a predetermined threshold (step <NUM>). In this regard, the components that are not scrapped may include a microtexture level indicator that is below the predetermined threshold. This may allow the selected components to provide enhanced service life compared to the scrapped components. By determining components for use in service in this manner, a service life of a fleet of components may be maximized.

In the detailed description herein, references to "one embodiment", "an embodiment", "various embodiments", etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic.

Claim 1:
A method, comprising:
scanning a plurality of regions of a component (<NUM>) with an ultrasonic transducer (<NUM>);
calculating a microtexture level indicator for each region in the plurality of regions;
characterizing a limiting region in the plurality of regions, the limiting region corresponding to a maximum microtexture level indicator;
comparing the microtexture level indicator of the plurality of regions, wherein the microtexture level indicator consists of a peak factor and wherein the peak factor is calculated based on a peak factor equation: <MAT>
wherein the peak amplitude corresponds to the maximum value of backscattered noise containing ultrasonic waves reflected by microstructures in the component and received by the transducer within a pre-defined gate recorded at an associated scanning position.