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.