TiAl金属间化合物解理断裂行为的研究

Study on the cleavage fracture behavior of intermetallic alloy TiAl

通过三点弯曲预裂纹试样在室温（２５ ℃）和 ７００ ℃的断裂试验，对接近 γ和全层状 α＋ γ的两种 Ｔｉ Ａｌ金属间化合物的解理断裂行为进行了研究．经过断口的详细观察和裂纹尖端应力、应变的有限元计算确定解理断裂的临界阶段．结果表明解理断裂是由预制裂纹的直接扩展所引发，由加工硬化决定的裂尖处的正应力是决定性的控制因素．

Cleavage fracture behavior of both near γ and fully lamellar TiAl intermetallic alloys was investigated by using pre cracked specimens with three point bending at room temperature and 700 ℃, respectively. Detailed observations of fracture surface and FEM calculations of stress and strain at crack tip were carried out to find the critical stage of cleavage fracture. The results show that the cleavage fracture is initiated by direct propagation of the pre crack and that the stress at the crack tip due to work hardening is the decisive controlling factor.