Ni-Al_xNi_y core–shell structured particle reinforced Al-based composites fabricated by in-situ powder metallurgy technique

Ni-Al_xNi_y core–shell structured particle reinforced aluminum based composites were fabricated using in-situ powder metallurgy method. Scanning electron microscope, X-ray diffraction, density analysis, hardness and compressive tests were used to investigate the effects of volume fraction of Ni particles and sintering atmosphere on the microstructures and mechanical properties of the composites. It has been shown that compared to Ar sintering atmosphere, N₂ atmosphere is active sintering atmosphere for fabricating the composites. The AlN formed during the sintering process, which can substantially increase the density and hardness of the composites. The strength of the composites sintered under N₂ atmosphere is higher than that of the composites sintered under Ar, while the ductility is slightly lower. It can be confirmed that the Ni-Al_xNi_y core–shell structures are of great benefit not only to increase the strength but also to remain the plasticity of the composites. - Highlights: • A new metal matrix composite (MMC) has been developed. • The developed MMC has a matrix/shell/core structure. • The developed MMC has both high strength and plasticity