Effect of LSP parameters on the corrosion and hardness properties of TI6Al4V

Abstract

Because of its low density, high corrosion resistance and high strength to weight ratio, titanium and its alloys are widely used in aerospace applications. As a result, the material is exposed to detrimental environment. An enhancement in surface integrity of the alloy is believed to have the potential to prevent the materials from experiencing premature failure in these aggressive environments. One of the promising surface modification techniques for improving the properties of metals is laser shock peening (LSP), which induces compressive residual stresses in the surface of layer of alloy and results in an increase in strength and fatigue life of the part. In the present study, Laser shock peening is employed to modify the microstructure, mechanical properties and corrosion behaviour of LENS-built titanium alloy components. The surface roughness, microstructural evolution, microhardness and corrosion behaviour of the LENS-built is examined before and after laser shock peening treatment. The effect of LSP overlaps on the corrosion and hardness properties of wrought titanium alloy and LENS-built were investigated. LSP treatment with 90, 95 and 99% overlapping were chosen. The mechanical behaviour of the Ti6Al4V was characterized by material hardness measurements to assess the effect of the peening process on material properties. The microstructure of the peened samples revealed a homogeneous a + ß phases. Electrochemical tests indicated that LSP improved the corrosion resistance of Ti6Al4V in sodium chloride. In addition, the hardness of Ti6Al4V increased from 375 HV before LSP to 389 HV after LSP. These results demonstrated that LSP is a promising surface modification method that can be used to improve the mechanical properties and corrosion resistance of Ti6Al4V.