Influence of B4C on microstructural, mechanical and wear properties of Mg-based composite by two-step stir casting

Abstract

This paper has been focused on the porosity, hardness, tensile and abrasion wear of Mg-based B₄C composites developed by squeezed vacuum-based stir casting (SVSC) process by adding 3, 5, 7, 9 wt. % of B₄C. Also, an electromagnetic stir casting has been used to synthesize similar composition specimens in comparison to the SVSC results. Additionally, electron microscopy has been used for analyzing the micro structural, fractographic and worn images of Mg-based B₄C composites and to validate appropriate fabrication method. A tribo-test has been carried out by two-body abrasion condition at 20N and 30N load for as sliding distance of 100m and 5m/s of speed. The results reveal that the SVSC process produces homogeneously distributed B₄C particles in Mg-matrix as compared to the electromagnetic stirring. The mechanical properties of Mg/B₄C composites show their significant enhancement with the addition of B₄C content in Mg-matrix. B₄C composites show an increment of 33-48% of hardness as compared to Mg-matrix. Mg-matrix having 9 wt. % of B₄C composite reveals the least tensile strength and fractured images show the cleavage planes, micro voids as well as micro cracks. Although, worn images shows oxidation and ploughing mechanism with the increase in load and depth of penetration in Mg-matrix B₄C composites.