EBSD and FIB/TEM examination of shape memory effect deformation structures in U–14 at.% Nb

Detailed examinations of shape memory effect (SME) deformation structures in martensite of U–14 at.% Nb were performed with electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). An accommodation strain analysis, which has been previously used to predict SME deformation structures and texture evolution in polycrystalline material, was also performed. Martensite variants and twin relationships observed with EBSD after compressive or tensile deformation were determined to be consistent with those expected from calculated accommodation strains. Focused ion beam (FIB) was used to select twinned regions identified with EBSD for more detailed TEM analysis to verify the presence of these specific twins. The observed SME twinning systems in the martensite agree with previous TEM observations and the predicted {1¯76} twinning system was observed experimentally for the first time in U–14 at.% Nb using these complementary techniques.