循环载荷下TiNi记忆合金涂层表面裂纹扩展驱动力分析

Study of crack driving force in TiNi shape memory alloy coating subjected to cyclic loading

TiNi记忆合金在一定温度范围内具有超弹特性(SE)的重要力学特征。把TiNi合金作为涂层材料可以有效地增强涂层的抗裂能力,延长涂层的使用寿命,是一种具有良好应用前景的功能涂层材料。本文通过数值模拟分析了循环载荷下TiNi记忆涂层表面裂纹的力学响应,研究了裂尖应力应变场及相应的裂纹扩展驱动力,并与常规涂层进行了对比分析,为TiNi记忆涂层的工程应用提供了一定的力学基础。

The superelasticity effect of TiNi alloy occurred in a certain temperature range was the unique mechanical characteristics of shape memory alloy (SMA). Due to the existence of recovering force, this functional material can prevent or retard the crack growth at a high level. As an advanced coating material TiNi shape memory alloy will enhance the coating's toughness and prolong the service life of whole coating/substrate system. In the present paper the finite element method was employed to simulate the behavior of TiNi SMA coating. The strain fields and the crack driving force of TiNi coating containing surface crack were investigated and compared with the normal coating material. The advantage of TiNi coating was revealed which provides the fundamental mechanical knowledge for the application of TiNi SMA coating in engineering.