Synthesis and mechanical properties of TiB₂/Ti₂AlN composites fabricated by hot pressing sintering

Abstract

TiB₂/Ti₂AlN composites with different proportions were successfully fabricated through solid state reaction of Ti/Al/AlN/BN powders and subsequent hot pressing sintering. The reaction mechanism, microstructures and mechanical properties of the composites were investigated. The Vickers hardness of the samples ascended with increases in the TiB₂ content and reached the highest value of 11.32 ± 0.12 GPa at a TiB₂/Ti₂AlN mole ratio of 1:2 (M2T1). TiB₂/Ti₂AlN composites with a mole ratio of 1:3 (M3T1) and 1:4 (M4T1) exhibited the maximum flexural strength of 497 ± 15 MPa and the highest fracture toughness of 9.52 ± 0.14 MPa·m^1/2, respectively, which are 1.3 times and 1.8 times that of pure Ti₂AlN (MT0) ceramic.