Synergistically enhanced strength and ductility of TiB/(TA15-Si) composites: A two-step HIP strategy

A novel two-step hot isostatic pressing strategy has been brought up to fabricate a kind of TiB/(TA15-Si) composites. The densification process and the process of introducing TiB reinforcement by in-situ synthesized reaction were separated. As a result, a network distribution of TiB reinforcement was achieved, and a bimodal matrix grain structure was regulated. By comparing the mechanical properties of the composites fabricated by traditional hot isostatic pressing method, we found that this novel strategy enhanced the yield strength and ultimate tensile strength by 9.6% and 11.0%, respectively. Moreover, the elongation was also improved from 4.7% to 6.6%. Through theoretical calculation and quasi-in-situ characterization, the strength enhancement was determined to be contributed by grain boundary strengthening, and the ductility was benefited by the bimodal structure of titanium matrix.