增材制造TC4钛合金在激光抛光前后的电化学腐蚀性能

对表面已进行喷砂处理的增材制造TC4钛合金在氩气环境下进行激光抛光实验,通过极化曲线测试研究了抛光前、后钛合金的耐蚀性,并结合表面粗糙度、晶粒尺寸、表面残余应力以及显微组织分析了激光抛光对TC4钛合金耐蚀性的影响。研究结果表明:抛光钛合金的自腐蚀电位与自腐蚀电流密度均大于未抛光钛合金,说明抛光钛合金相比于原始钛合金的被腐蚀倾向更小,但其一旦受到腐蚀,腐蚀速率会略大于原始钛合金。自腐蚀电位的升高源于钛合金表面粗糙度的降低,自腐蚀电流密度的增大则是因为表面晶粒的细化以及残余拉应力的存在。

Electrochemical Corrosion Behaviors Before and After Laser Polishing of Additive Manufactured TC4 Titanium Alloy

In this study,laser polishing experiment of the additive manufactured TC4 titanium alloy with abrasive blasting is conducted in argon gas.Further,a polarization curve is plotted to verify the corrosion resistances of the surface before and after laser polishing and to analyze the effect of laser polishing on the corrosion resistance of the TC4 titanium alloy based on the surface roughness,grain size,surface residual stress,and microstructures.The results denote that the self-corrosion potential and self-corrosion current density of the polished surface are greater than those of the initial surface,indicating that the polished surface exhibits a lesser corroded tendency when compared with that exhibited by the initial surface.However,if the polished surface corrodes,its corrosion rate is observed to be slightly greater than that of the initial surface.The increase in self-corrosion potential can be attributed to the decrease in the surface roughness of the material.Furthermore,the increase in self-corrosion current density can be attributed to grain refinement and residual tensile stress on the surface.