中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 10 No. 5 October 2000 |
WANG Yan-bin(王燕斌)1, CHEN Chang-qi(陳昌鹿其)1, CHU Wu-yang(褚武揚)1
（1. Department of Materials Physics, University of Science and Technology Beijing,
Beijing 100083, P.R.China;
2. Department of Materials Science and Engineering,
Beijing University of Aeronautics and Astronautics, Beijing 100083, P.R.China）
Abstract:The fracture mechanism of lamellar Ti-49%Al alloy was investigated through studying the interactions between crack and lamellae or grain boundary. The results indicated that the nucleation and propagation mechanisms of crack depends on not only the lamellar orientations within grain but also the types of grain boundaries. When the angle between tensile axis and lamellae is relatively large, the main crack parallel to the lamellae propagates by nucleation, growth and linkage with interfacial microcracks. When the tensile axis is nearly parallel to the lamellae, the main crack perpendicular to the lamellae propagates by nucleation, growth and linkage with two types of microcracks, e.g. translamellar microcrack and interface delamination. In addition, the interlock grain boundary nearly parallel to the tensile axis is benefit to fracture toughness, the grain boundary nearly perpendicular to the tensile axis is bad for the toughness.
Key words: TiAl alloy; lamellae; crack; grain boundary; fracture mechanism
