Compression behavior of Al2O3sf/Mg-6Al-0.5Nd-1Gd composites fabricated by pressureless infiltration and semi-solid densification

Short fiber reinforced magnesium matrix composites containing rare earth elements (Al2O3sf/Mg-6Al-0.5Nd-1Gd composites) were fabricated by pressureless infiltration and semi-solid densification. The effect of combined addition of rare earth elements and short fiber on the compression strength and strain hardening behavior of the composites was investigated. The results showed that the refinement and reduction of β-Mg17Al12 phases, the formation of thermally stable Al2RE and Mg2Si phases, and the moderate interfacial bonding enhanced the compression strength of the composites by 45.8% compared to the Mg-6Al alloys at room temperature. The composites also exhibited good strengthening effect even at temperatures above 200 °C, and the relative improvement in compression strength still reached 48.5% at 300 °C. The strain hardening exponents of the composites (evaluated using Hollomon's equation) were also increased greatly, which range from 0.43 to 0.87, and far greater than that of the Mg-6Al alloys (0.05-0.53).