Meisam K. Habibi

An investigation into the effect of ball milling of reinforcement on the enhanced mechanical response of magnesium

Magnesium composites containing as-received and ball-milled (B) Al particles were synthesized through powder metallurgy route using microwave-assisted rapid sintering technique followed by hot extrusion. Microstructural characterization revealed fairly uniform distribution of both as-received and ball-milled (up to 1.626 vol.%) Al particles in the matrix and reduction in average matrix grain size. Compared to monolithic Mg, Mg/Al, and Mg/Al (B) composites exhibited significantly higher strengths and failure strains. The results revealed that strength and failure strain (up to 1.626 vol.% Al) of composites containing ball-milled Al particles remained higher compared to composites containing as-received Al particles. Compared to monolithic Mg, Mg/1.626Al (B) composite exhibited the best mechanical properties improvement with an increase of 78%, 79%, 87%, and 225%, in 0.2%YS, UTS, failure strain and WOF, respectively, while for Mg/1.626Al composite, the improvement was 51%, 53%, 65% and 142%, respectively. The effects of as-received and ball-milled Al particles contribution on the enhancement of mechanical properties of Mg is investigated in this article.

Development of hierarchical magnesium composites using hybrid microwave sintering.

Abstract In this work, hierarchical magnesium based composites with a micro-architecture comprising reinforcing constituent that is a composite in itself were fabricated using powder metallurgy route including microwave assisted rapid sintering technique and hot extrusion. Different level-I composite particles comprises sub-micron pure aluminum (Al) matrix containing Al2O3 particles of different length scale (from micrometer to nanometer size). Microstructural characterization of the hierarchical composites revealed reasonably uniform distribution of level-I composite particles and significant grain refinement compared to monolithic Mg. Hierarchical composite configurations exhibited different mechanical performance as a function of Al2O3 length scale. Among the different hierarchical formulations synthesized, the hierarchical configuration with level-I composition comprising Al and nano-Al2O3 (0.05 pm) exhibited the highest improvement in tensile yield strength (0.2% YS), ultimate tensile strength (UTS), tensile failure strain (FS), compressive yield strength (0.2% CYS) and ultimate compressive strength (UCS) (+96%, +80%, +42%, +80%, and +83%) as compared to monolithic Mg. An attempt has been made in the present study to correlate the effect of different length scales of Al2O3 particulates on the microstructural and mechanical response of magnesium.