The Effect of Heat Treatment on Promoting the Precipitation of Al2cu and its Influence on the Tribological Properties of Plasma-Sprayed Alsi30cu5 Coating

Abstract

To further enhance the wear resistance of AlSi30 coating, this study introduced Cu element, which could react with Al to form θ-Al2Cu reinforcing phases. Plasma spraying technology was utilized to prepare both AlSi30 and AlSi30Cu5 coatings, and the AlSi30Cu5 coating underwent appropriate heat treatment (330 °C for 24 hours). Subsequently, wear resistance tests were conducted on the AlSi30, AlSi30Cu5, and heat-treated AlSi30Cu5 (HT-AlSi30Cu5) coatings at room temperature and high temperature (210 °C). The impact mechanism of heat treatment on the precipitation of θ-Al2Cu and its influence on tribological properties were discussed in detail. The results indicated that, compared to the AlSi30 and AlSi30Cu5 coatings, the HT-AlSi30Cu5 coating exhibited reduced porosity, a denser microstructure, and smoother and rounded Si phases without significant size increase. After aging heat treatment, a large number of submicron-sized θ-Al2Cu high-temperature stable reinforcing phases precipitated within the AlSi30Cu5 coating, providing significant dispersion strengthening to the coating. This is a crucial factor enabling the HT-AlSi30Cu5 coating to maintain excellent wear resistance at both room temperature and 210 °C, improving by 51% and 38% respectively compared to the AlSi30Cu5 coating.

Keywords: Keyword: AlSi30 coating, AlSi30Cu5 coating, heat treatment, microstructure evolution, wear resistance