Effect of Spark Plasma Sintering on Microstructure and Properties of TiB₂/AlCoCrFeNi Composites

Abstract

The equal molar AlCoCrFeNi high entropy alloys with 5% (volume fraction) TiB2 particles reinforcement were fabricated by spark plasma sintering (SPS). Effect of SPS temperature and pressure on microstructure evolution and mechanical properties of TiB2/AlCoCrFeNi composites was studied using X-raydiffraction (XRD), density testing, scanning electron microscopy (SEM) and mechanical properites testing. The results show that increasing SPS temperature and pressure can improve hardness and compressive strength of TiB2/AlCoCrFeNi composites. The relative density, compressive strength, yield strength and hardness of the TiB2/AlCoCrFeNi composite after sintering at 1200℃ and 30MPa are 99.6%, 2416MPa, 1474MPa and 470HB, respectively. During spark plasma sintering, phase transformation occurs in the high entropy alloy matrix of the composite. The composite after sintering at 1200℃ and 30-45MPa is composed of phases BCC, B2, FCC, TiB2 and σ.

Keywords

• high entropy alloy matrix composite
• spark plasma sintering
• density behavior
• microstructure
• mechanical property