Abstract
High strengthened magnesium alloys were developed by employing grain-refined coarse powder via roll compaction (RCP) process. The conventional powder metallurgy (P/M) process, consisting of cold compaction and hot extrusion with an extruding ratio of 37, was applied to fabricate the grain-refined powder into full dense. The grain size strongly depends on the number of cycles in RCP process, for example the mean grain size of 4μm and 1.1μm in 30 and 50 cycles, respectively were observed in optical microstructures. The micro-hardness and tensile strength increase with increase in the number of cycles in RCP. The hot extruded AM60 alloy in using the powder after 50 cycles indicates 370MPa UTS and elongation of 20%. The mechanical properties are extremely superior, compared to the conventional P/M magnesium alloys. Newly developed magnesium alloys, ZAXE1713 (Mg-1Zn-7Al-1Ca-3La/mass%), via RCP and hot extrusion process, show a good balance of high strength and ductility, such as 410MPa UTS and elongation of 17% at room temperature.
