Mechanical characterization of eggshell ash and boron carbide reinforced ZA-27 hybrid metal matrix composites

Abstract

This study aimed at discovering the influence of low-cost eggshell ash (ESA) and boron carbide (B4C) addition on microstructure and mechanical characteristics of ZA-27 hybrid composites. Six different composites were fabricated utilizing the stir casting technique with different weight percentages of ESA and B4C particles varied from 0-5 wt.%. Composites were tested for density, hardness, compressive strength, tensile strength, and impact strength. X-ray diffraction (XRD) and scanning electron microscope (SEM) were utilized for the characterization of composites. Microstructure examination using SEM exhibited homogeneously dispersed reinforcements in the matrix. ESA particles decreased the composite density by 3.12%, and after the addition of B4C particles, density was found to be increased but was still lower than the base ZA-27 alloy. The hardness, tensile and compressive strength of the composites increased with the addition of reinforcements. However, composite reinforced with maximum wt.% of B4C particles showed a decreasing trend. The impact strength of the composites decreased when compared with the base alloy, but the reduction was marginal. Improved hardness, tensile and compressive strength of the composites was attributed to homogeneously dispersed ESA and B4C particles in the matrix. Higher tensile strength resulted from strong interfacial bonding between reinforcements and metal matrix, and low impact strength was due to brittle failure and plastic deformation.