基体界面屈服强度和残余应力失配对界面裂纹扩展的影响

对基体界面屈服强度和残余应力失配情况下的界面裂纹扩展机制进行了力学理论分析,并通过位错与裂纹的关系理论计算了界面裂纹尖端塑性区尺寸。结果表明:当界面裂纹由低强度区向高强度区扩展时,高强度区的残余压应力和屈服强度减少了裂纹尖端的塑性区长度和裂纹尖端张开位移,从而起到了抑制界面裂纹扩展的作用。

AEffect of mismatch of yielding strength and residual stresses along substrate interface on interfacial crack propagation

The mechanism of crack propagation at the interface between coating and substrate was analysed under the condition of yielding strength and residual stress mismatches along the interface. The dimension of plastic zone at the crack tips was numerically calculated using the correlative theory of dislocation and crack. Calculation results show that when the interfacial crack propagates from low strength zone to high strength zone, the residual compressive stress and yielding strength of the high strength zone lead to the reductions of the length of plastic zone and the opening displacement of crack tip. As a result the propagation of the crack at the interface is retarded.