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采用脉宽30 ns,能量40 J的调Q掺钕玻璃激光对TC4钛合金钨极惰性气体(TIG)焊焊缝进行了1~3次的激光冲击强化(LSP)处理,并与未经LSP处理的焊缝的表面显微硬度、焊缝微观组织、接头的拉伸力学性能和拉伸断口的扫描电镜(SEM)照片进行比较,研究LSP处理次数对TC4钛合金TIG焊焊缝组织性能的影响。结果表明,LSP能够使焊缝横截面靠近材料表面的区域针状α′相数量减少,热影响区靠近材料表面的区域细小等轴晶数量增加;随着LSP处理次数的增加,TC4钛合金TIG焊接头表面的显微硬度增加;焊接接头的抗拉强度和屈服强度变化不明显,而断后延伸率出现降低趋势。
A Q-switched neodymium-doped glass laser with a pulse width of 30 ns and an energy of 40 J was used to perform laser shock strengthening (LSP) of 1 to 3 times on the TIG weld of TC4 titanium alloy. The surface microhardness, the microstructure of the weld, the tensile mechanical properties of the joint and the scanning electron micrograph (SEM) of the tensile fracture were compared. The results showed that the number of LSP treatment on the microstructure and mechanical properties of TIG weld of TC4 titanium alloy influences. The results show that LSP can reduce the amount of acicular α ’phase in the region close to the surface of the weld and increase the number of fine equiaxed grains in the HAZ near the material surface. With the increase of LSP treatment times, The microhardness of the welded joint surface increased; the tensile strength and yield strength of the welded joint did not change obviously, but the elongation after fracture showed a decreasing trend.