Effect of solidification conditions on microstructure, mechanical and wear properties of Mg-5Al-3Ca-0.12Sr magnesium alloy

In the present study, the microstructure, mechanical and wear properties of AXJ530 alloy under different solidification condition were investigated. AXJ530 alloys were cast in a multi-step permanent mould casting (PMC) with five different cooling rates, and also in high pressure die casting (HPDC). The effect of cooling rate was determined for the room temperature mechanical properties and the dry sliding wear resistance of the AXJ530 alloys. The results showed that grain size of AXJ530 alloy was refined and thinner lamellar eutectic phase formed at higher cooling rate. It was concluded that these changes led to the observed concurrent increases in ultimate tensile strength (sigma(uts)), yield strength (sigma(0.2)) and elongation (delta) of the AXJ530 alloy. The relationship between grain size and yield strength/hardness agreed with Hall-Patch behavior. The dry sliding wear rate of the PMC specimens decreased with increasing of cooling rate, but micro-porosity/inclusion in the HPDC specimen decreased its wear resistance properties. Abrasion was determined to be the dominant wear mechanism for the AXJ530 alloys. (C) 2010 Elsevier Ltd. All rights reserved.