Influence of applied pressure on microstructure and tensile properties of squeeze cast magnesium Mg-Al-Ca alloy

This paper reports the effect of applied pressure on the tensile properties and the microstructure of squeeze cast Mg-5 wt.% Al-1 wt.%Ca (AX51) alloy. In this study, applied pressures from 3 to 90 MPa were considered. It was observed that the fraction of second phases and porosity level reduces with an increase in applied pressure. The tensile tests results indicate that ultimate tensile strength (UTS), yield strength (YS) and elongation (E-f) of AX51 alloy increase with increasing applied pressures. The improvement in tensile properties was attributed to the casting densification and presence of higher amount of solute in the matrix. The scanning electron microscopy (SEM) fractographs reveal that the fracture modes of the squeeze cast alloy is more ductile at higher applied pressures. The crack initiation occurred mostly in the vicinity of Mg-Al-Ca particles. (C) 2011 Elsevier B.V. All rights reserved.