Microstructure and Mechanical Properties of Ni-Based Alloy Composite Coating on Cr12MoV by Laser Cladding

Abstract

Cr12MoV has been widely used in the manufacture of stamping and drawing dies. In the present study, an attempt was made to improve the mechanical properties of Cr12MoV by laser cladding Ni60 alloy reinforced by WC. X-ray diffraction (XRD), scanning electron microscopy (SEM), a microhardness tester, and a friction and wear test prototype were used to analyze the macroscopic morphology, microstructure, and mechanical properties of the coating. The results showed that the coating mainly was composed of Cr-Fe-Ni, γ-(Fe, Ni), Cr23C6, Cr7C3, and W2C phases. The cladding layer presented the dendritic eutectic structure enriched Cr, Fe, and Ni. Zigzag-shaped dendrites with thicknesses of 50~80 μm of the bonding zone ensured the strong metallurgical bonding. Due to solid solution strengthening, dispersion hardening, and grain refinement, the hardness of the coating reached 745 HV, which was 3.5 times that of the substrate. The wear volume of the coating was 14 × 10−3 mm3, which was 48% lower than that of the substrate (27 × 10−3 mm3). The coating had the abrasive wear; however, the substrate had the adhesive wear besides the abrasive wear.