Effect of TiN on microstructure and wear resistance of Fe–Cr–C hardfacing alloy: experimental research and first-principles calculation

Abstract

Fe–Cr–C coatings with and without TiN additive were developed by harden-surface welding. The effect of TiN on the wear resistance and microstructure of the surfacing layer in the surfacing layer were discussed. Analyze the refining mechanism of TiN on primary M7C3 with first-principles calculation. The Rockwell hardness tester was used to examine the hardness of the surfacing layer. Abrasive wear was test by wet grinding wheel wear tester. X ray diffractometer (XRD), scanning electron microscope (SEM), energy spectrum analyzer (EDS), Transmission electron microscope (TEM) and other equipment were used for testing and analysis. The results show that in the hardfacing layer containing TiN, the primary M7C3 was significantly smaller than that without TiN. As the TiN content increases, the hardness and wear resistance of the surfacing layer increase accordingly. The thermodynamic and kinetic calculations show that the two-dimensional misfit of TiN/M7C3 is 8.43%, and TiN can be used as a heterogeneous nucleus for primary M7C3. Based on the experimental study, the interfacial energy of Fe3Cr4C3 (0001)/TiN (111) was calculated by first-principles calculations. The interfacial energies of Fe3Cr4C3 (0001)/TiN (111) were lower than those of nucleation in iron-based melts. It indicates that TiN can be used as the heterogeneous nucleation base of primary M7C3, which is consistent with the experimental analysis.