Effect of B4C on microstructure and wear performance of FeCrNiTiZr laser cladded coatings

FeCrNiTiZr + xB4C coatings have been fabricated on H13 by laser cladding, and the effects of B4C on the phase composition, microstructure, microhardness, and wear resistance of the coatings have been analyzed. The microstructure of 8% B4C and 12% B4C coatings is mainly composed of eutectic structures (which consist of BCC solid solution and Fe2B), along with a large number of dendrites and ZrC hard particles, while the microstructure of 16% B4C and 20% B4C coatings transform into equiaxed grains and dispersed hard particles. The addition of B4C leads to significant solid solution strengthening, grain refining strengthening, and dispersion strengthening in the coatings. The average microhardness of the coatings is 4.36–5.35 times that of H13. The 16% B4C coating has the highest microhardness (1069 HV0.2). Under room temperature wear conditions, the wear volume of the coatings is 72%–88% lower than that of H13. During the wear process, the oxide film formed on the surface of 16% B4C coating effectively protects the coating, resulting in the best wear resistance (wear volume: 0.015 mm3). During high temperature (350, 450, and 550 °C) wear tests, compared with H13, the wear volume of the 16% B4C coating decreased by 86%, 86%, and 85%, respectively. The high-temperature wear resistance is significantly improved.