激光冲击强化与热处理复合工艺对TC4钛合金表面性能的影响

Effect of Laser Shock Peening and Heat Treatment Composite Process on the Surface Properties of TC4 Titanium Alloy

为研究激光冲击强化(LSP)与热处理(HT)对TC4钛合金表面性能的影响,对TC4钛合金试样进行激光冲击强化处理,利用显微硬度仪与电化学工作站对冲击强化与热处理前后的表面进行表面硬度和耐腐蚀性能的表征,利用激光共聚焦显微镜、扫描电镜(SEM)对冲击强化与热处理前后的表面与截面的形貌和微观组织进行表征。结果显示,经过一次和两次冲击强化的试样,表面硬度分别达到425.4 HV和456.5 HV,相比原始试样提高12.3%和20.5%,对一次、两次冲击强化试样进行热处理后,表面硬度进一步提高,分别达到465.1 HV和483.2 HV。耐腐蚀性能方面,激光冲击强化后TC4试样的自腐蚀电位发生了正移,腐蚀电流密度下降。一次和两次冲击强化后,试样的腐蚀速率相比原始试样分别降低36.2%和4%,耐腐蚀性能提升。热处理之后,TC4试样自腐蚀电位向负移动,腐蚀电流密度上升,腐蚀速率提高,耐腐蚀性能下降。

In order to investigate the effect of laser shock peening(LSP)and heat treatment on the surface properties of TC4 titanium alloy,LSP was applied to TC4 titanium alloy specimens.The surface hardness and corrosion resistance of the surfaces before and after LSP and heat treatment were analyzed by using microhardness tester and an electrochemical workstation.The surface and cross-sectional morphology and microstructure were analyzed through laser confocal microscopy and SEM.The results show that the surface hardness of the specimens strengthened by one and two LSP impacts reached 425.4 HV and 456.5 HV respectively,an increase of 12.3%and 20.5%compared to the original specimen.After heat treatment,the surface hardness of specimens further increased to 465.1 HV and 483.2 HV respectively.The self-corrosion potential was positively shifted and the corrosion current density decreased after LSP.The corrosion rate of the specimens was reduced by 36.2%and 4%compared to the original specimen after one and two impacts,respectively.After heat treatment,the self-corrosion potential of TC4 specimens shifted negatively,the corrosion current density increased,the corrosion rate increased,and the corrosion resistance decreased.