Microstructure and mechanical properties of Al–Si–Ni–Ce alloys prepared by gas-atomization spark plasma sintering and hot-extrusion

Al–Si–Ni–Ce alloys with the composition of Al78.5Si19Ni2Ce0.5, Al76Si19Ni4Ce1 and Al73Si19Ni7Ce1 were atomized and then sintered by using spark plasma method. The microstructure of the as-atomized powders, sintered and hot-extruded samples was analyzed. The influences of granularity and sintering parameters including time and temperature on the density of sintered alloy were also discussed. It is shown that the atomized powders are composed of Si, Al11Ce3, Al3Ni and alpha Al. Tiny Al3Ni particles precipitate from supersaturated matrix near the powder boundaries during SPS. Hot-extrusion process leads to the layer structure and more homogeneous distribution of precipitates. These alloys exhibit high comprehensive mechanical properties with combination of high Vickerʹs micro-hardness, moderate tensile properties and elongation, which provide a novel kind of promising engineering materials.