Microstructure Evolution and High Temperature Performance of Cold Sprayed Aluminium 6061- Al2O3 Nanocomposite

Among all structural materials, only a limited number of composite powders are customized for cold spray printing. Powder mixing can be an alternative to developing new composite materials; however, simple dry mixing of the powders may not work due to inhomogeneous distribution. This research introduces nanoparticle decoration as an alternative for mixing powders. Al6061 decorated with Al₂O₃ nanocomposite was selected as a model material. Both pure Al6061 and decorated Al6061-Al₂O₃ powders were printed on an aluminum substrate using a high-pressure cold spray system. The effect of Al₂O₃ nanoparticles on microstructure evolution and mechanical properties during age-hardening heat treatment and monotonic hot compression test was investigated. This study demonstrated that grain boundary pinning by Al₂O₃ nanoparticles effectively limits grain growth and grain boundary mobility during the solutionizing process or hot deformation. Hence, a finer and more stable final microstructure leads to significant enhancement in the mechanical properties of the printed samples.