Enhancing overall tensile and compressive response of pure Mg using nano-TiB2 particulates

Abstract

A novel attempt is made to synthesize and study the isolated effects of less than two volume fraction TiB2 nanoparticulates (60nm) on pure magnesium. New light weight Mg–TiB2 nanocomposites with superior mechanical properties compared to pure magnesium are synthesized using disintegrated melt deposition technique followed by hot extrusion. The microstructural characterization studies revealed that the samples exhibited fairly uniform distribution of TiB2 nanoparticulates with minimal porosity and good interfacial integrity between Mg matrix and TiB2 particulates. The coefficient of thermal expansion results indicates that the addition of 0.58, 0.97, and 1.98vol.% TiB2 nanoparticulates marginally improves the dimensional stability of pure magnesium. A significant improvement in the room temperature tensile properties of pure magnesium was observed with the addition of less than two volume fraction TiB2 nanoparticulates. The synthesized Mg 1.98vol.% TiB2 nanocomposite revealed the best room temperature tensile properties with a significant increase in the 0.2% tensile yield strength by ~54%, ultimate tensile strength by ~15% and fracture strain by ~79% when compared to pure Mg. The X-ray diffraction studies indicated changes in the basal plane orientation of pure Mg with the addition of nano-TiB2 particulates. A maximum tensile fracture strain of ~16% is achieved with the addition of 0.97vol.% TiB2. The room temperature compressive properties of the nanocomposites reveal that the addition of 1.98 TiB2 increases the 0.2% compressive yield strength of Mg by ~47% and ultimate compressive strength by ~10% with a marginal increase in the fracture strain (~11%). Reduction in tensile–compression yield asymmetry was observed for Mg 0.58 & 0.97vol.% TiB2 nanocomposites which can be attributed to the weakening of the strong basal texture of pure Mg.