EFFECTS OF SIC PARTICULATES ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF AZ91 MAGNESIUM MATRIX COMPOSITES

摘要

In this study, monolithic AZ91 alloy and AZ91 magnesium matrix composites reinforced with three different fractions (10, 15, 25 wt.%) of SiC particulates (SiCp) were fabricated by rapid solidification and powder metallurgy technique followed by hot extrusion. Microstructure and mechanical properties of these alloys were examined. The addition of SiCp could weaken basal plane texture. Microstructure of AZ91 alloy showed fine grains about 1μm. The composites revealed that SiCp were relatively homogeneous dispersed with few agglomerations. The porosity and hardness increased as the content of SiCp increased. An increase in particulate reinforcement content was observed to decrease ultimate tensile strength but increase yield strength and elongation of the composite. The reason of degraded mechanical properties was due to increasing agglomerating regions, porosity and brittle interface debonding.