Method for ultrasonic evaluation of materials using time of flight measurements
AssigneeGeneral Electric Company
InventorsEdward J. Nieters, Robert S. Gilmore, Michael F. X. Gigliotti, Jr.
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Abstract
A nondestructive evaluation method is described for ultrasonic evaluation and detection of features in polycrystalline materials, such as grain orientation (e.g. texturing) or grain boundary orientation. The method may, for example, be employed to detect diffusion bonds that contain undesirable planar grain boundary arrays. The method utilizes time of flight statistics gathered from reflections associated with incident ultrasonic signals directed into a plurality of locations within the material.
Claims19
A method of detecting and evaluating microstructural features comprising regions of grain orientation or crystallographic texture, grain boundary orientation or grain size differential within a volume of a material having a microstructure comprising a plurality of randomly oriented grains defining a randomly oriented network of grain boundaries, comprising the steps of:
- insonification of a plurality of locations within the volume of the material by using a transducing means to send an ultrasonic pulse through each location, whereby the ultrasonic pulse produces at each location a plurality of reflections characteristic of the microstructure of the material at that location, each reflection having a characteristic amplitude and time of flight;
- detection of the amplitude and the time of flight for each of the plurality of reflections at each location;
- identification of a time of flight (TOF.sub.M) value of the reflection at each location having the largest amplitude;
- storing information comprising the TOF.sub.M value at each location and the associated location in an information storage means;
- and
- comparing the value of TOF.sub.M at one location with the values of TOF.sub.M at a plurality of other locations for the purpose of determining whether a region of adjacent locations exist having the same TOF.sub.M, whereby a region of adjacent locations having the same values of TOF.sub.M are indicative of grain orientation or grain boundary orientation within the material.
A method of evaluating an article formed by bonding together a plurality of materials, each material having a microstructure comprising a plurality of randomly oriented grains defining a randomly oriented network of grain boundaries, and containing an internal interface where the materials are bonded to one another, comprising the steps of:
- insonification of a plurality of locations within the article, including locations that comprise the internal interface, by using a transducing means to send an ultrasonic pulse through each location, whereby the ultrasonic pulse produces at each location a plurality of reflections characteristic of the microstructure of the materials at that location, each reflection having a characteristic amplitude and time of flight;
- detection of the amplitude and the time of flight for each of the plurality of reflections at each location;
- identification of a time of flight (TOF.sub.M) value of the reflection at each location having the largest amplitude;
- storing information comprising the TOF.sub.M value at each location and the associated location in an information storage means;
- and
- comparing the value of TOF.sub.M at one location with the values of TOF.sub.M at a plurality of other locations for the purpose of determining whether a region of adjacent locations exist having the same TOF.sub.M, whereby a region of adjacent locations at the internal interface having the same values of TOF.sub.M are indicative of incomplete bonding between the materials.
Dependencies are inferred from the claim text.