Development of Heat-Resistant Magnesium Composites by Bulk Mechanical Alloying Method

Abstract

The utilization of the magnesium alloy in the engine parts of the automobiles and motorcycles is expected to improve fuel efficiency. But the creep resistance at 150°C∼250°C is required in the engine parts, which prevents the use of the magnesium alloy. In this research, AM60 magnesium alloy chip mixed with 10 volume percent calcium oxide powder was processed into a magnesium composite billet, in which the calcium oxide powder was finely and uniformly dispersed, by the Equal Channel Angular Bulk Mechanical Alloying (ECABMA) method. The composite billet was extruded at 450°C into a round bar, whose diameter was 20 mm or 40 mm. The mechanical properties of the extruded magnesium composites, such as the creep resistance at 175°C, were investigated. The extruded magnesium composite was found to have the higher strength at room temperature and 250°C, and the higher creep resistance at 175°C than those of the ADC12 aluminum alloy.