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对Ti-5Al-4Mo-4Cr-2Sn-2Zr钛合金进行了不同能量和冲击次数的激光冲击强化,通过残余应力、显微硬度、XRD和TEM分析其对力学性能和微观组织的影响。结果表明,功率密度和冲击次数对残余应力和显微硬度都有较大影响,激光冲击强化后,显微硬度和残余应力都有大幅度提升,并形成一定厚度的变形层,增加冲击次数或者增大功率密度都可提高其幅值和影响深度。不同冲击参数下的XRD测试表明,激光冲击强化后衍射峰位置没有发生变化,但有展宽。激光3次冲击后可在表面形成一层纳米晶,晶粒大小为30~60 nm,且取向随机。位错运动是Ti-5Al-4Mo-4Cr-2Sn-2Zr钛合金晶粒细化的主要原因。
The laser shock strengthening of Ti-5Al-4Mo-4Cr-2Sn-2Zr titanium alloy with different energy and impact times was carried out. The residual stress, microhardness, XRD and TEM were used to analyze the mechanical properties and microstructure. The results show that both the power density and the number of impacts have a significant effect on residual stress and microhardness. After laser shocking, the microhardness and residual stress both increase greatly, and a certain thickness of deformed layer is formed, increasing the number of impacts or Increase the power density can increase its amplitude and depth of influence. The XRD results of different impact parameters show that there is no change in the diffraction peak position after laser shock strengthening, but with a broadened width. After three times of laser shock, a layer of nanocrystal can be formed on the surface, the grain size is 30 ~ 60 nm, and the orientation is random. Dislocation motion is the main reason for grain refinement of Ti-5Al-4Mo-4Cr-2Sn-2Zr titanium alloy.