(1. 北京科技大学 材料物理系， 北京 100083;
2. 北京航空航天大学 材料科学与工程系， 北京 100083)
摘 要: 通过单轴压缩及TEM原位拉伸研究了全层状TiAl合金(PST晶体)中α2板条的形变和断裂特征。结果表明，全层状TiAl合金中α2相形变和断裂特征与加载方向有关。当片层与加载轴平行时，α2相中的滑移沿柱面进行，微裂纹优先在α2相内(沿柱面)形核；而当片层与加载轴垂直时，形变困难，α2相中的滑移将沿角锥面进行，微裂纹很容易沿相界面形核、扩展。
关键字: 全层状TiAl合金；α2板条； 形变； 断裂
fully lamellar TiAl alloys
（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 deformation and fracture characteristics of α2 plates in fully lamellar TiAl alloys (PST crystals) were investigated through uniaxial compression and insitu TEM technique. The results indicate that the deformation and fracture characteristics of α2 plates in fully lamellar TiAl alloys are related to the loading direction. When the lamellae are parallel to the loading axis， the slips in α2 plates occur along prism planes and microcracks form preferentially within α2 plates (along prism planes); when the lamellae areperpendicular to the loading axis， the deformation is relatively difficult， and the slips in α2 plates occur along pyramidal planes and microcracks form easily and propagate along γ/α2 interfaces.
Key words: fully lamellar TiAl alloy; α2 plates; deformation; fracture
