Microstructure and mechanical properties of SiCp/Mg-Al-Zn composites containing Mg17Al12 phases processed by low-speed extrusion

Without solution treatment, the 5 µm10 vol% SiCp/Mg-Al-Zn magnesium matrix composites containing Mg17Al12 phases were extruded at 593 K and 693 K with a constant speed of 3 mm/s. Results demonstrated that the Mg17Al12 phases precipitated along grain boundaries in the as-cast composite were cracked to fine particles after hot extrusion. The amount and size of Mg17Al12 phase were influenced obviously by extrusion temperature. The basal plane texture was formed during hot extrusion, however, the intensity of basal plane texture strengthened with increasing extrusion temperature, which was different from previous reports. The yield strength, ultimate tensile strength and elongation of the present composite extruded at 593 K is 310±8 MPa, 395±4 MPa and 3.8±0.5%, respectively, which exhibits better tensile properties than previous researches.