Low-Temperature Densification Mechanism and Mechanical Properties of W-Fe-C Composites

Abstract:

The W-Fe-C composites were prepared using spark plasma sintering at various sintering temperatures, and their sintering behavior, phases, microstructure, and mechanical properties were characterized. The densification mechanism was also analyzed. The results show that as the temperature increases, the reinforcement phase in the composite transitions from Fe₆W₆C to Fe₃W₃C, and finally to Fe₂W₂C. After sintering at 1400 ℃, the sample achieves a relative density of 99.2%, with an ultimate compressive strength of 2455.15 MPa and a deformation rate of 25.42%. During the holding stage, the W-Fe-C composite exhibits a unique creep recovery stage, where the densification rate is nearly zero. When the effective stress exponent (n) is approximately 1 and 2, the estimated activation energies are 341.27 and 1005.73 kJ/mol, respectively, which are higher than those of pure tungsten. However, because the in-situ reaction promotes diffusion, the relative density of the W-Fe-C composites exceeds that of pure tungsten. This study provides a new approach for the low-temperature fabrication of tungsten-based composites.