Damping capacities and tensile properties in Grp/AZ91 and SiCp/Grp/AZ91 magnesium matrix composites

Grp/AZ91 and SiCp/Grp/AZ91 magnesium matrix composites were fabricated by stir casting with graphite particle size of 50 μm and SiC particle size of 10 μm. The as-cast composites were extruded at 350 °C with an extrusion ratio of 12:1. The experimental results reveal that the reinforcements play an important role on the tensile properties and damping capacities of the composites. The addition of graphite particles improves the yield strength, and the addition of SiC particles further improves the yield strength. The addition of graphite particles improves the strain amplitude independent damping, but the addition of reinforcements does not change the critical strain significantly. Temperature dependence of damping capacities in as-cast and as-extruded materials both can be divided into two regions, and each region has different dominant damping mechanisms.