中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 10 No. 3 June 2000 |
alloys at room temperature①
（1. Department ofEngineering Mechanics,
Southwest Jiaotong University, Chengdu 610031, P.R.China;
2. Division of Super Alloys, Central Iron and Steel Research Institute, Beijing100081, P.R.China）
Abstract:The tensile mechanical properties and fracture behaviors of Ti-22Al-20Nb-7Ta alloys were studied at room temperature. Three typical microstructures of Ti2AlNb based alloys were obtained by combination of thermal mechanical processing and heat treat-ment. They are: 1) lath mixture ofO+B2 with remainingβgrain boundaries andα2phase; 2) equiaxedOphase inB2 matrix; 3) fine lath mixture ofO+B2 without remainingβgrain boundaries. It is shown that the microstructure obviously affects the tensile properties of Ti2AlNb based alloys. The microstructure of fine lath
mixture ofO+B2 without remainingβgrain boundaries has good combination of yield stress and ductility, while the microstructure with lath mixture ofO+B2 with remainingβgrain boundaries andα2phase has low yield stress and elongation. The fracture mode was also controlled by the microstructure of Ti2AlNb based alloys. By means of SEM, it was found that the dominated fracture mode of microstructure with lath mixture ofO+B2 with remainedβgrain boundary andα2phase was intergranular, and the fracture mode of the other two microstructures was mainly transgranular.
Key words: Ti2AlNb based alloys; tensile properties; fracture behavior
