The effect of Ti and B4C powder sizes on the mechanical and thermal properties of (TiC + TiB)/Ti titanium matrix composites

Four titanium matrix composites made of pure Ti (10–53 μm and 53–150 μm) and two raw B₄C powders (50 nm and 1 μm) were synthesized by powder metallurgical method. The microstructure, mechanical, and thermal properties of the composites were investigated. The microstructures of composites made from 10 to 53 μm Ti powders are nearly uniform, while those made from 53 to 150 μm Ti particles show typical network architectures. The lengths and aspect ratios of the reinforcements increased as raw B₄C particles increased. The combination of fine Ti and nano-sized raw B₄C particles possessed the highest yield strength of 636.3 ± 2.5 MPa, while the combination of coarse Ti and micro-sized B₄C particles led to a yield strength of 602.3 ± 0.9 MPa. The formation of network microstructure improved thermal conductivity through the increase of phonon mean free paths and effective heat transfer channels.