XRD Stress Analysis in a TiAl Based Intermetallic Multicrystal
Under specific manufacturing processes and heat treatments, the gamma titanium Aluminide Ti- 47Al-2Cr-2Nb presents a nearly lamellar microstructure with coarse lamellar grains (with alternating g and a2 lamellae) and dispersed small g grains. The obtained microstructure gives a relatively coarse grain size (approximately 0.4 mm x 3 mm). Residual stresses can then be generated between g and a2 lamellae inside the lamellar grain and also between different grains because of the lattice mismatch between tetragonal structure of g phase and hexagonal structure of a2 phase. A specific single crystalline XRD method is applied on these two non-cubic phases to determine the local residual stresses in two grains on each side of a grain boundary.
Sabine Denis, Takao Hanabusa, Bob Baoping He, Eric Mittemeijer, JunMa Nan, Ismail Cevdet Noyan, Berthold Scholtes, Keisuke Tanaka, KeWei Xu
W. Seiler et al., "XRD Stress Analysis in a TiAl Based Intermetallic Multicrystal", Materials Science Forum, Vols. 490-491, pp. 684-689, 2005