Influence of B ₄ C content and particle size on the mechanical properties of Al ₂ O ₃ ‐B ₄ C composites

Abstract Alumina (Al 2 O 3 ) ceramics and their composites are widely used in the cutting tool industries due to their superior mechanical properties. This study presents a comprehensive investigation of the influence of B 4 C content and particle size on the sinterability, microstructure, and mechanical properties of Al 2 O 3 ‐B 4 C composites fabricated using Spark Plasma Sintering (SPS). The relative density of the composites increased and residual porosity decreased as the B 4 C particle size in the powder blends decreased. The addition of B 4 C particles improved the mechanical properties of monolithic Al 2 O 3 and the highest property enhancements were obtained for the composite with 30 vol% of the finest B 4 C particles. For this composition, with respect to monolithic Al 2 O 3 , the density was reduced by 11% and hardness, Young's modulus, indentation fracture toughness, and flexural strength increased by 24%, 8%, 51%, and 88%, respectively. The effect of the B 4 C particle size on the Young's modulus in relation to existing micromechanical models reveals that the composites with a fine B 4 C particles fit the Reuss model.