2020/05/29 by Rachel E. Lim, Lim, Rachel E., Darren C. Pagan +9
Engineering · Materials Science · #Intermetallics and Advanced Alloy Properties #Boron and Carbon Nanomaterials Research #Titanium Alloys Microstructure and Properties
paper · pdf · doi:10.48550/arxiv.2006.00065
Hexagonal metals have anisotropic coefficients of thermal expansion causing\ngrain-level internal stresses during heating. High energy x-ray diffraction\nmicroscopy, a non-destructive, in situ, micromechanical and microstructural\ncharacterization technique, has been used to determine the anisotropic\ncoefficients of thermal expansion (CTEs) for Ti-7Al. Two samples of\npolycrystalline \α-phase Ti-7Al were continuously heated from room\ntemperature to 850 ^\∘C while far-field HEDM scans were collected. The\nresults showed a change in the ratio of the CTEs in the 'a' and 'c' directions\nwhich explains discrepancies found in the literature. The CTE additionally\nappears to be affected by the dissolution of \α2 precipitates. Analysis\nof the grain-resolved micromechanical data also shows reconfiguration of the\ngrain scale stresses likely due to anisotropic expansion driving\ncrystallographic slip.\n