Effect of cerium and aluminium on the hot-deformation behaviour of magnesium

Abstract

Abstract This study examines the response of pure Mg and its alloys, both binary Mg–Ce and ternary Mg–Al–Ce, during compression testing over a wide range of (true) strain rates and temperatures. Process maps were generated by plotting the instability parameter and efficiency of energy dissipation for microstructural evolution as a function of test temperature and strain rate. Microstructural features of each of the deformed samples were examined to generate a microstructure/micromechanism map as a matrix that was overlaid on the process map drawn in the temperature–strain-rate space. The combination of both maps delineated the desirable “safe” process window for each of the materials. Addition of 0.5% Ce to pure Mg reduced the extent of the “safe” process window despite increasing the flow stress, while alloying with both Ce and Al widened this window as determined by the extent of the desirable DRX domain. The process maps in general suggest a much wider range of temperature and strain rate for “safe” deformation compared to the microstructure maps.