Effect of extrusion temperatures on microstructure and mechanical properties of SiCp/Mg–Zn–Ca composite

SiCp/Mg–Zn–Ca composite fabricated by stir casting was extruded at three different temperatures. Firstly, hot extrusion significantly improved particle distribution and refined the grains of the matrix. Even, nano-grains were observed in the composite extruded at 250 °C. Secondly, extrusion evidently refined the size of the second phases, but also changed the distribution of the second phases. Extrusion temperatures obviously affected the size and distribution of the second phases. Thirdly, the interface between SiCp and matrix was also modified by hot extrusion. Finally, all as-extruded composites possessed good mechanical properties. Below 150 °C, the UTS was very high in the extruded composites, but their strengths decreased sharply above 150 °C.

► Novel SiCp/Mg–Zn–Ca composites were fabricated and extruded.
► Nano-grains were observed near SiCp.
► Evolution of second phases during extrusion affected mechanical properties of composites.
► Extrusion temperatures significantly influenced mechanical properties of composites.