Achieving the synergistic strength and wear resistance in TiC/Fe matrix composites by spark plasma sintering and hot isostatic pressing

The iron matrix composites reinforced with titanium carbide particles (TiC/Fe MCs) with high strength and excellent wear resistance had been fabricated through spark plasma sintering (SPS) and hot isostatic pressing (HIP) post-treatment in this study. The effects of different HIP temperatures on the porosity, microstructure, interface, and mechanical properties of the composites had been systematically investigated. The results indicated that the microstructure of both the composites fabricated by SPS and HIP post-treatment consists of TiC, FeCr, (Ti, Mo)C, Al 2 Mo 3 C, and Cr 21 Mo 2 C 6 phases. Under HIP post-treatment conditions at 1410°C, the composite exhibited a hardness of 628 HV0.5, a bending strength of 1006 MPa, a coefficient of friction (COF) of 0.56, and a wear rate of only 4.6 ×10 -5 mm 3 /m. Compared to samples fabricated by SPS alone, the porosity decreased from 3.85 % to 0.08%, the hardness increased by 5.5 %, the bending strength improved by 52.0%, the COF decreased by 24.3 %, and the wear rate decreased by 61.7 %. After SPS process, the fracture surfaces of the samples exhibited a higher prevalence of intergranular fracture, whereas transgranular fracture was predominant following HIP post-treatment at 1250°C. The primary strengthening mechanisms of the composite included fine-grain strengthening and enhanced densification. During friction and wear testing, fatigue wear, oxidative wear, and plastic deformation predominantly affected the SPS samples and the samples treated with HIP post-treatment below 1250°C. However, abrasive wear, plastic deformation, and oxidative wear primarily influenced the samples with HIP post-treatment above 1250°C.