Interface characterization and mechanical properties of Mo-added chromium carbide-nickel composite 1

Abstract A novel chromium carbide–nickel composite was in situ fabricated through pressureless sintering in a vacuum furnace using Cr, C, Ni and Mo mixed powders. In this study, the Mo content distribution on interface characterization including the effect of phase transformation mechanism and mechanical properties of the composite were researched thoroughly. The results indicated that a newly found and excellent semi-coherent boundary existed between Cr3C2 and Ni, which was (002)Cr3C2//(11 1 ( _ ) )Ni, [1 2 ( _ ) 0]Cr3C2//[011]Ni. Their disregistry along the particular orientation relationship was approximately 10.6%, indicating that Cr3C2 could serve as an efficient heterogeneous nucleation area of Ni. An interdiffusion and phase transformation occurred in the microstructure, Mo element tended to solid solute into the carbide matrix which changed from (Cr, Ni)3C2 to (Cr, Mo)3C2, and (Cr, Mo, Ni)7C3. Moreover, according to DFT calculation for contain phases as well as the Rockwell hardness, bending strength, and fracture roughness were enhanced simultaneously, it was attributed to grain refinement, solution strengthening, and better mechanical properties of the (Cr, Mo, Ni)7C3 phase.