Effect of deep cryogenic treatment on microstructural, physical, and mechanical response of a microwave processed Mg-Fe metal-metal composite

A Mg-15Fe (wt.%) metal matrix composite synthesized with powder metallurgy and followed by microwave sintering was studied alongside cryogenic treatment (CT) for the first time. Results revealed that CT was able to alter the microstructure of the composite, with grain refinement (23% reduction in diameter), densification (2.0% increase), and basal texture strengthening. These resulted in enhanced thermal stability (2.4%), elastic modulus (3.2% increase), hardness (10% increase) and yield strength (7.3% increase) at the cost of reduced damping capacity (24% reduction), and ductility (15.4% reduction). Minor thermal changes were also noted of Mg-15Fe with more endothermic nature of CT treated samples. These findings showcase, for the first time, the application of CT in altering the microstructure of a Mg-based Metal-metal composite.