激光冲击钛合金表面退火后的残余应力分布

选用钛合金Ti-6Al-4V进行激光冲击成形实验，发现其表面产生很大的残余拉应力和残余压应力。对不同后处理工艺条件下表面的残余应力进行了研究，结果发现：钛合金成形凹面具有良好的力学性能稳定性，其表面残余压应力不会随着退火温度的提高而降低；而其成形凸面的残余拉应力随着退火温度的提高逐渐消退，在371℃退火后，钛合金凸面上82．67％的残余拉应力消除，剩余残余拉应力仅为20．6MPa。经过高温退火后的钛合金具有良好的抗疲劳性能，可以满足飞机结构件的使用要求。

Study of Annealing Treatment on Residual Stresses of Titanium Alloy during LSP

The effect of laser shock processing(LSP)on titanium alloys Ti-6Al-4V was tested.It was found that a residual compressive stress and tensile stress were caused on the surfaces of alloys.The alloys were placed in an elevated temperatures environment in the service temperature range of interest and then their residual stresses were measured.The results showed that after four hours at the elevated temperature environment the residual compressive stress was almost recovered to its minimum surface stress,while the residual tensile stress to 82.67% at its convex surface and only a small residual tensile stress(20.6 MPa)left at its convex surface.Results of the experiments indicate that the fatigue resistance and damage tolerance of alloys are greatly improved after annealed,which can satisfied the demand of the aircraft engine parts and aircraft structures.