Abstract
Nickel base superalloy and aluminium single crystal and polycrystalline specimens have been examined using mechanical property microprobe (MPM) measurements and electron backscatter patterns (EBSPs) as a function of applied strain. Grids of lines deposited on to the specimens before three point bending were used to determine the macroscopic strain. The MPM, or nanoindenter, has been used to produce arrays of five by three indents across the edge of the specimens, both before and after bending. Electron microscope film EBSPs have been produced from regions within the nanoindenter arrays. The effects of strain can be seen in the change in Kikuchi band profile and thus EBSP ‘image quality’ and in changes in the hardness of the sample. Software is being developed to quantify these differences. It has been found that when the nickel base superalloy calibration specimens were bent, stress relief occurred by the formation of slip bands. This caused problems with strain calibration, and alternative methods are being investigated.
MST/3677
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