Effects of supersonic fine particle bombardment on the microstructure and corrosion properties of Ti-6Al-3Nb-2Zr-1Mo alloy

The surface of Ti-6Al-3Nb-2Zr-1Mo (Ti80) alloy was treated with supersonic fine particle bombardment (SFPB) for different time durations from 30 s to 90 s. The effects of different SFPB time on the microstructure and corrosion properties of the specimens were systematically investigated. The surface grains of the specimens with different SFPB treatment time were all refined and formed surface nanostructures, and the surface microhardness increased by 23.9 %, 31.8 % and 39.6 %, respectively, compared with the untreated specimens. After SFPB, compressive residual stress (CRS) was generated in the specimens, with maximum CRS of Ti80 alloy specimens at different SFPB time were-423 MPa,-451 MPa and-487 MPa, respectively. The results of electrochemical and immersion experiments showed that the corrosion rate of SFPB-treated specimens was reduced, and the passivation effect was best at 60 s of SFPB treatment and decreased with the increase of SFPB treatment time. The SFPB treatment improved the corrosion resistance of the specimens, which was the result of the combined effect of grain refinement and surface CRS.