Enhancement of high temperature oxidation and hot corrosion resistance behaviors of selective laser melted Ti6Al4V by ultrasonic shot peening

Abstract

In the present study, Ultrasonic shot peening (USSP) method has been adopted to understand the electrochemical corrosion resistance, high temperature oxidation and hot corrosion resistance of Ti alloy (Ti6Al4V) fabricated by Selective Laser Melting (SLM) process. The results showed the significant enhancement in electrochemical corrosion resistance in 3.5 wt% NaCl, high temperature oxidation resistance and hot corrosion resistance in Na₂SO₄ + 25 % NaCl and Na₂SO₄ + 50 % V₂O₅ at 750 °C after the USSP treatment. Various characterization techniques such as Optical Microscopy, Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and Field Emission Scanning Electron Microscopy (FE-SEM) used to characterize the high temperature oxidation as well as the hot corrosion products and the result confirms the formation of various oxide compounds such as TiO₂, Al₂O₃, V₂O₃, V₂O₅, Na₂TiO₃ etc. Grain size have been significantly reduced from 62.4 ± 6.5 to 39.3 ± 3.4 μm and it substantially improved the hardness value from 386 to 457.5 HV after USSP treatment.