|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||Shot Peening Induced Microstructural Stability of a High Nb Containing TiAl Alloy during High Temperature Exposure
||Lu Fang, Xian Fei Ding, Junpin Lin
|On-Site Speaker (Planned)
High Nb containing TiAl alloys have attracted particular attentions in aerospace and automobile industries, due to their outstanding performances for high temperature applications. Shot peening process has been used in surface hardening and modification of the alloys for improving the fatigue performance. Therefore, the microstructural instability induced by shot peening was investigated in a Ti-45Al-8.5Nb-(W, B, Y) alloy during high temperature exposure. After thermal exposure at 900 ℃ or 1000 ℃ for 100-300h, a depth-dependent gradient microstructure was produced in the surface. Two typical layers, a fine-grained layer with equiaxed shape and a coarse-grained layer with elongated morphology, were formed in transversal direction. Most of the new grains in the two layers were γ single phase, while short α2 segments and few B2 particles precipitated at the γ/γ interface or inside the γ grains. Recrystallization and phase boundary bulging were found to be the major mechanisms responsible for lamellar degradation.
||Planned: A print-only volume