残余应力对GH4169微观疲劳裂纹扩展行为的影响OA

This study used GH4169 alloy as the research object and employed microscopic single-edge notched tension(M-SENT)specimens with cracks.Different magnitudes of uniformly distributed loads were applied to the upper and lower sides of M-SENT specimen models with varying constraints to induce different stress levels at the crack tip.This stress was introduced into the specimens as a residual stress.Based on the established microscopic fatigue crack propagation(MPFCP)model,the influence of the interaction between residual stress and constraint on the microscopic fatigue crack propagation(MFCP)behavior of GH4169 alloy was systematically investigated.The results indicate that at a strain ratio of R=0,the fatigue crack propagation(FCP)rate under high constraint is more sensitive to changes in residual stress;at R=-1,the sensitivity of the fatigue crack growth rate to residual stress variations is relatively similar across different constraint levels.For all specimens with varying constraints,there exists an optimal residual stress level.Under high constraint conditions,the fracture life at R=0 is longer than that at R=-1.