Microstructure and tensile properties of laser melting deposited TiC/TA15 titanium matrix composites

TiC/TA15 titanium matrix composites were fabricated by laser melting deposition (LMD) process. Microstructures and room temperature tensile properties of the composites were evaluated as a function of TiC volume fraction. Majority of the TiC reinforcement was in equiaxed or near-equiaxed particles in the as-deposited composites. Average size of the TiC particulates are 8.6-11.2 μm as the TiC volume fraction increases from 5% to 15%. Tensile tests indicated that the composite containing 5 vol.%TiC showed better strength compared to monolithic matrix, while tensile properties of the composites deteriorated with further increasing TiC volume fractions. The damage mechanism of the composites is dominated by particle cracking followed by ductile failure of the matrix. The decrease of tensile strength of composites with TiC volume fractions higher than 5% was mainly attributed to the premature failure of the blocky coarse and agglomerated TiC reinforcements during tension, and the degradation in ductility of the composites.