Microstructure, mechanical properties and wear behaviors of in-situ nanophase enhanced Al matrix composites fabricated by selected laser melting

To illustrate the influence of in-situ self-generated nano-phases on the microstructure and properties of composites. In this study, aluminum (Al) matrix composites with different CuO contents (0, 1, 3, and 7 wt%) were fabricated by selective laser melting (SLM). The results show that the self-generated nano-phases (Al 2 Cu precipitates and Al–Cu solid solution) were obtained, and their content with an increase in CuO content. The composite with 7 wt% CuO exhibits the best strength and ductility synergy, with a yield strength increase by 222.2% compared to pure Al while maintaining a fracture strain of 30.9%. Orowan strengthening of Al 2 Cu precipitates account for more than 60% to the total strength enhancement. Furthermore, the wear rate of Al/7%CuO composite decreased by 69.3% than pure Al, and the wear mechanism transitioned from abrasive to oxidative wear with an increase in CuO content. This work not only provides an approach for exploring in-situ self-generated nano-phase reinforced Al matrix composites, but also develops a direction for the application of SLM.