The effects of adding micro-scaled niobium carbide on the microstructure, mechanical strength and polarization resistance of the Ti–8Mo–4Co-xNbC composites

The objective of our research was to add the strengthening phase carbide to the matrix Ti–Mo–Co powder alloy for enhancing its mechanical properties. Various amounts of strengthening niobium carbide powders were decomposed with titanium matrix then niobium dissolved with titanium as substitutional solid solution strengthening phase of the β titanium stabilizer. And, the produced titanium carbide was a solid solution strengthening phase dispersedly in purpose to increase its strength. This studying examined the strengthening phase of thermo-stabilization after the heating process were simultaneously vacuum sintered at sintering temperatures of 1200, 1250 and 1300 °C for 1 h, respectively. Meanwhile, the relative density, apparent porosity, hardness and transverse rupture strength (TRS) and the microstructure were also examined. The results showed the hardness was enhanced slightly, however, the strength of alloys was enhanced by added niobium carbide as a reinforcing element effectively for increasing the mechanical properties of TRS from 1133.0 to 1229.7 MPa. Simultaneously, the volume shrinkage was 25.0%, the polarization resistance was 2450.2 Ω cm2, and the relative density increased to 98.1%. •NbC as a strengthening phase of the Ti–8Mo–4Co alloy increased the TRS and HRA.•NbC additive decomposed and solved with Ti as solid solution strengthening.•NbC additive could refine the grain size and be the β phase Ti stabilizer.•NbC additive could reduce Widmanstätten-like phase and refine the α in β grain.