Mechanical behavior of porous magnesium/alumina composites with high strength and low density

Porous alumina-reinforced magnesium composites were synthesized through a powder metallurgical method and characterized using optical microscope, scanning electron microscope, and compression testing. The microstructural study exhibited that the average pore sizes increased with the increase of porosity and were about 25 mu m, 70 mu m, and 100 mu m for the samples with 10%, 28%, and 38% porosities respectively. The mechanical characterization indicated that (i) the stress-strain curves were composed of three regimes: an initial regime that deformed elastically along an approximately linear line, a long and intermediate regime, and a densification regime with a steep increase of stress; (ii) the synthesized porous magnesium composites possessed lower density and higher yield strength than those of cast dense magnesium; (iii) the average yield strength and Young's modulus were anisotropic for the porous magnesium composites synthesized in this work. (C) 2013 Elsevier B.V. All rights reserved.