新型光斑搭接对平顶激光冲击钛合金力学性能的影响

To simplify the process and improve the efficiency, a novel overlapping method was proposed. The novel overlapping rate was set as longitudinal 25% and lateral 56.5%. The residual stress, micro-hardness, and high cycle fatigue limit of the titanium alloy after laser treatment with this overlap were investigated. The comparison of the above mentioned mechanical properties between the new overlap and the traditional 50% overlap was also studied. Results show that the mean value of surface compressive residual stress induced by laser shock peening (LSP) is –564.5 MPa with the new overlap, and the influenced depth reaches 0.81 mm. With the traditional overlap, the surface compressive residual stress induced by LSP is –564.5 MPa and the depth of compressive residual stress is 0.82 mm. The surface micro-hardness of titanium alloy after LSP at more overlapping regions are 570.9 and 562.6 HV0.3 and that at less overlapping regions are 432.1 and 453.4 HV0.3, respectively. The layer of compressive residual stress after LSP are both 0.4 mm. The high cycle fatigue limit of titanium alloy after LSP are 256.3 and 264.6 MPa with the new and traditional overlapping rates, respectively. Based on the flat-toped laser beam, the mechanical properties of the titanium alloy after LSP with this novel simplified overlapping rate process can be obtained as same as that with 50% overlapping rate. The processing efficiency increases and the cost is reduced.