Copper powder ultrasonic shot peening and its application in antifouling of Ti alloy

Abstract

This study develops a new shot peening method, i.e., copper powder ultrasonic shot peening, and investigates its antibiofouling effect on commercially pure titanium grade 2 (TA2) alloy in seawater. The results indicate that adding Cu powder during ultrasonic shot peening can form a Cu-containing layer with a thickness 1–2 μm on the surface of TA2 alloy, primarily in the form of nanocrystals. This Cu-containing layer exhibits a 90 % antifouling efficiency against Pseudomonas aeruginosa and an 85 % efficiency against Aspergillus terreus, mainly due to the release of Cu ions during immersion. Electrochemical corrosion test results show that corrosion rate of this anti-fouling layer is two orders of magnitude higher than the substrate alloy, which significantly enhances the release of Cu ions and thereby improving the antifouling capability. Tensile test results show that Cu powder peening similarly improves the mechanical properties of TA2 alloy as conventional peening.