A Comprehensive Experimental and Modeling Study of the Strain Rate- and Temperature-Dependent Deformation Behavior of Bio-Degradable Mg-Ceo2 Nanocomposites

Abstract

A comprehensive study was undertaken on the temperature-dependent and strain rate-sensitive deformation behavior of near-dense low-volume fraction magnesium-cerium dioxide (Mg-CeO2) nanocomposites synthesized by powder metallurgy technique. The process involved ball milling of elemental powders -> cold compaction -> sintering in an inert atmosphere, and in-situ hot extrusion. The Mg-CeO2 nanocomposites displayed strain rate and temperature sensitivity, exhibiting higher yield strength, superior compressive characteristics, greater hardness, and improved ductility compared to pure Mg and most commercial Mg alloys. Furthermore, a thorough micro-structural investigation was conducted to characterize the distributions of ceria nanoparticles, grain refinement degree, ceria-magnesium interface, formation of deformation twins and interfacial bonding between the reinforcement and matrix. The present study has proposed two modeling approaches, the Johnson-Cook (J-C) constitutive model and a machine learning-assisted model, to predict the mechanical behavior of monolithic Mg and Mg-CeO2 nanocomposites. The models effectively explained the deformation behavior under various strain rates and temperatures.