Evolution of Microstructures and Mechanical Properties of Sr and Ca Containing Mg-4Al Alloy during Annealing Heat Treatment
Microstructures, mechanical and creep properties of as-cast and as-annealed Mg-4Al-2Sr-1Ca (AJX421) alloy were investigated. The as cast microstructures of the alloy consists of the α-Mg, lamellar eutectic Mg2Ca and bulky Mg-Al-Sr phase. After annealing at 400°C, lamellar eutectic tended to be spheroidised and the continuous interphase network breaks up gradually, meanwhile, C14-Mg2Ca completely transforms to C15-Al2Ca. These results in obvious decrease of creep property. It is proposed that the continuous network distribution of compounds paly a major role in restricting the creep deformation of Mg-Al alloy at elevated temperatures, and the grain boundary sliding is an important creep mechanism for the alloy studied.
J. Bai et al., "Evolution of Microstructures and Mechanical Properties of Sr and Ca Containing Mg-4Al Alloy during Annealing Heat Treatment", Advanced Materials Research, Vols. 311-313, pp. 772-777, 2011