Designing high-temperature oxidation-resistant titanium matrix composites via directed energy deposition-based additive manufacturing

Composite material development via laser-based additive manufacturing offers many exciting advantages to manufacturers; however, a significant challenge exists in our understanding of process-property relationships for these novel materials. Herein we investigate the effect of input processing parameters towards designing an oxidation-resistant titanium matrix composite. By adjusting the linear input energy density, a composite feedstock of titanium-boron carbide-boron nitride (5 wt% overall reinforcement) resulted in a highly reinforced microstructure composed of borides and carbides and nitrides, with variable properties depending on the overall input energy. Crack-free titanium-matrix composites with hardness as high as 700 ± 17 HV(0.2/15) and 99.1% relative density were achieved, with as high as a 33% decrease in oxidation mass gain in the air relative to commercially pure titanium at 700 °C for 50 h. Single-tracks and bulk samples were fabricated to understand the processing characteristics and in situ reactions during processing. Our results indicate that input processing parameters can play a significant role in the oxidation resistance of titanium matrix composites and can be exploited by manufacturers for improving component performance and high temperature designs.