喷丸强化AZ91 D镁合金残余应力场的数值模拟及实验研究

目的研究喷丸工艺对AZ91D镁合金表面残余应力场的影响。方法基于有限元平台建立喷丸强化AZ91D镁合金的有限元模型,从残余压应力层的厚度、残余压应力的峰值及其深度等方面探讨弹丸速度、弹丸直径和弹丸入射角对AZ91D镁合金表面残余应力场的影响,并通过喷丸强化AZ91D镁合金的实验与有限元模拟结果进行对比。结果增大弹丸速度对残余压应力层的厚度、残余压应力的峰值提高效果明显,但对残余压应力峰值的深度影响不大;增加弹丸直径,残余压应力层的厚度、残余压应力的峰值及其深度均有明显提高;增大入射角,残余压应力层的厚度、残余压应力的峰值有明显提高,但是残余压应力峰值的深度基本不变。有限元模拟结果中,残余压应力层的厚度比实验值小7%,残余压应力的峰值比实验值大5%,残余压应力峰值的深度比实验值小11%。结论残余应力的实验结果与有限元模拟结果具有较好的一致性,模型合理。

Numerical Simulation and Experimental Study of Residual Stress Field of AZ91D Magnesium Alloy by Shot Peening

Objective To study the impact of the shot peening process on surface residual stress field of AZ91D magnesium alloy. Methods This paper established a finite element model of shot peening AZ91D magnesium alloy based on finite element platform and discussed the influence of pellet shot velocity, shot pellet diameter and incidence angle on the surface residual stress field of AZ91D magnesium alloy mainly from the aspects of the compressive residual stress layer thickness, the compressive residual stress peak and the depth of compressive residual stress peak. Besides, results of shot peening test and finite element simulation were compared. Results The compressive residual stress layer thickness and compressive residual stress peak increased significantly with the increase of shot velocity, but the increase of shot velocity had little influence on the depth of compressive residual stress. The compressive residual stress layer thickness, the compressive residual stress peak and the depth of compressive residual stress peak increased significantly with the increase of shot pellet diameter. By increasing the incidence angle, the compressive residual stress layer thickness and the compressive residual stress peak increased significantly, but the depth of the compressive residual stress peak value basically remained unchanged. The compressive residual stress layer thickness of finite element simulation was 7% smaller than the test results, the compressive residual stress of finite element simulation was 5% higher than the test results, and the depth of compressive residual stress of finite element simulation was 11% smaller than the test results. Conclusion Residual stress test results have good consistency with finite element simulation results, verifying the validity of the finite element model.