Tensile Creep and Microstructure of Magnesium-Aluminum-Calcium Based Alloys for Powertrain Applications - Part 2 of 2

This paper describes the tensile creep and microstructure of Mg-Al-Ca-based ACX magnesium alloys being developed for powertrain applications. Important creep parameters, i.e., secondary creep rate and creep strength, for the new alloys are reported. Tensile creep properties of the newly developed ACX alloys are significantly better than those of AE42 alloy, which is the benchmark creep-resistant magnesium die casting alloy. Creep mechanisms for different temperature/stress regimes are proposed. A new intermetallic phase, (Mg,Al)₂Ca, was identified in the microstructure of the ACX alloys, and is proposed to be responsible for the improved creep resistance of the alloys.