Preparation and mechanical properties of in situ TiCx-Ni (Si, Ti) alloy composites

Novel in situ TiCx reinforced Ni (Si, Ti) alloy composites with superior mechanical properties were prepared at 1250 C for 30 min by pressureless sintering Ti3SiC2 (10 and 20 vol%) and Ni as precursors. The Ti3SiC2 particles decomposed into substoichiometric Tic(x) phase, while the additional Si and partial Ti atoms derived from Ti3SiC2 diffused into Ni matrix to form Ni (Si, Ti) alloy. The in situ formed TiCx phases are mainly dispersed on the grain boundaries of the Ni (Si, Ti) alloying, forming a strong skeleton and refining the microstructures of the metal matrix. The hardness, the yield stress (sigma(0.2%) and ultimate compressive strength of 20.6 vol%TiCx-Ni(Si, Ti) composite can reach 2.15 +/- 0.04 GPa, 466.8 +/- 55.8 MPa and 7333 +/- 78.4 MPa, respectively. The enhanced mechanical properties of Tic(x)-Ni(Si, Ti) composites are due to the in situ formation of TiCx skeleton, the refined microstructures of Ni (Si, Ti) alloys and solid solution effects as well as good wettability between TiCx and Ni (Si, Ti) matrix. (C) 2014 Elsevier B.V. All rights reserved.