|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||GAT-2017 (Gamma Alloys Technology - 2017)
||Fracture Behavior during Hot Tension Testing of High Nb Containing TiAl Alloys
||Bin Zhu, Xiangyi Xue, Hongchao Kou, Lin Song, Jinshan Li
|On-Site Speaker (Planned)
Cracking during cooling process of castings or ingots seriously impedes the application of high Nb containing TiAl alloys. To understand this problem, fracture behavior during tensile tests of Ti-45Al-8.5Nb-(W, B, Y) alloy with as-cast microstructure was studied at low strain rates and various temperatures around brittle to ductile transition temperature(BDTT). It is shown that below BDTT, cracks initiated and lead to bulk fracture at a low strain. Above BDTT, the fracture elongation increased obviously. But some wedge cracks and cavities were observed at locations with low strain value on fractured specimens. These wedge cracks and cavities could form during cooling of TiAl components, and grow or propagate under thermal stresses at low temperatures. The initiation sites of cracks and cavities were observed associated with B2 phase and titanium borides above and below BDTT. This may provide a microstructural reason for cracking of TiAl alloys.
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