Effect of water jet peening using ultrasonic waves on pure Al and Al–Cu alloy surfaces

Abstract

Al has been widely used in many common products, such as household items, industrial products, and accessories. To respond to the increasing demand for its use, the enhancement of various properties of Al by adding different elements has been explored. As a result, numerous types of aluminum alloys have been developed, the addition of elements is a complex process, and the recycling of such alloys is difficult. In this study, the improvement of the residual stress, strength, and corrosion resistance of the surface of pure Al specimens by the multifunction cavitation (MFC) processing was investigated. Moreover, although the strength of Al–Cu alloys is greater than that of pure Al, the added Cu reduces the corrosion resistance; thus, the improvement of the corrosion resistance of the surface of Al–Cu alloy specimens by MFC processing was also explored. In the MFC-processed pure Al, water jet peening always suppressed the erosion generated in the center part of the specimen surface and improved the residual stress applied to the specimen surface. Furthermore, the MFC processing of the Al–Cu alloy was confirmed to improve the surface residual stress, strength, and corrosion resistance. Dissolved oxygen generated during processing is involved in the improvement of the corrosion resistance, and it is considered that the corrosion resistance was improved by the formation of an oxide film as a result of this dissolved oxygen bonding with Al on the surface.