Synthesis of a356 alloy-variable particle sized boron carbide composites: investigations on mechanical behaviour and tensile fractography

Abstract

Lightweight metal matrix composites made of aluminium are now essential in several fields, including aerospace and automotive. An important factor determining the quality and properties of the composite material is the ease or difficulty of evenly dispersing the reinforcement throughout the matrix. The goal of this research is to find out the impact of 40 and 90 µm varying- sized boron carbide (B4C) particles in A356 alloy composites. Using the liquid stir casting technique and K2TiF6 as the wetting flux, A356 alloy with 9 wt.% of B4C composites were prepared. SEM and EDS images were used to study the material’s microstructure. ASTM-approved methods were used to measure the material’s mechanical properties. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) confirmed that B4C particles were evenly distributed throughout the A356 alloy. The addition of B4C reinforcement to the A356 alloy matrix increased the hardness, ultimate, yield, compression, and impact strength of composites with a reinforcement size of 40 μm. The hardness of A356 alloy was enhanced by 40.7% and 34.6%, respectively, when 9 wt. % of 40 and 90 μm B4C were added. Similarly, there was a 34% increase in ultimate strength and a 31% improvement in yield strength. Both cases showed a little decrease in the ductility of the composites. Scanning electron micrographs were used to examine the morphologies of tensile fractured surfaces.

Keywords

• a356 alloy
• b4c particles
• microstructure
• tensile properties
• hardness
• impact strength