Mechanism Study on Forming Process of QT600 Laser Cladding Ni–Co Dual Phase Cladding Layer

Abstract

The preparation of Ni–Co dual phase cladding layer on the surface of ductile iron can effectively improve its wear resistance and corrosion resistance. Quantifying the forming process of Ni–Co composite cladding layer can provide an important theoretical basis for improving the service life of cladding layer. In this study, a three-dimensional numerical model and a molecular dynamics (MD) model of Ni–Co composite coating multi-layer cladding forming were established from both macroscopic and microscopic perspectives. The transient evolution of the temperature, height, energy, crystal structure and radial distribution function during Ni–Co composite coating multi-layer cladding forming were calculated and revealed. The results showed that the temperature of the first Ni-based cladding layer was slightly lower than that of the second Co-based cladding layer, and the height was slightly higher than that of the second Co-based cladding layer. When the first Ni-based cladding layer was formed, the content of FCC crystals was the highest, and the content of HCP and BCC crystals was very small. When the second Co-based cladding layer was formed, FCC crystals were the most, followed by HCP, BCC crystals were the least. The XRD results were consistent with the numerical results, which verified the reliability of the numerical calculation.

Graphical abstract