Fabrication and mechanical properties of metal matrix composite in Mg-Al-B systems

The powder metallurgy method was applied to prepare the particle-dispersed composite material with the addition of B in Mg-Al. The effects of manufacturing conditions on the structures and mechanical properties of the sintered compacts were investigated to find high strength and high functionality as an alloy. The sample composition of (Mg-9 %Al)-6.8 %B was produced by hot pressing and pressureless resintering. The powder was mechanical alloyed. Sintering temperature of 475 °C was adopted for the hot press, and with the sintering temperature controlled 600∼800 °C. The new composite material has following appearances and performances; (1) High strength was exerted by addition of B as reinforcing particles. (2) Mechanical alloyed (Mg-9 %Al)-6.8 %B by hot-pressed at 475 °C followed by resintered at 770 °C, showed the bending strength of 621 MPa and the Rockwell hardness of 116 HRH.