Microstructure and Properties of Laser Cladding Fe-VC Ultrafine Grained Layer on M2 High-Speed Steel
Longyun Yang, Guangchun Xiao, Hui Chen, Hui Zhang, Jingjie Zhang, Mingdong Yi, Zhaoqiang Chen and Chonghai Xu
In-situ VC-reinforced Fe-based ultrafine grained cladding layer (Fe-VCM) was prepared by the laser cladding technology. The effect of elements that reverse the transition from the M2 high-speed steel (HSS) substrate to the cladding layer on the microstructure and mechanical properties of the Fe-VCM cladding layer was studied. The results indicate that the cladding layer comprised α-Fe, γ, and (V, M) C (M=W, Mo, Cr), with (V, M) C composing the carbide network in the intergranular region. The Fe-VCM cladding layer obtained elements such as W, Mo, Cr, V, and C from the matrix, thereby significantly improving its microhardness, red hardness, and wear resistance through the solid solution and dispersion strengthening mechanisms. The Fe-VCM cladding layer exhibited microhardness that was 1.13 times higher, red hardness that was 1.25 times higher, and wear resistance that was 1.53 times higher than the HSS substrate. The main wear mechanism of the Fe-VCM cladding layer was abrasive wear. This study provides the theoretical and experimental basis to strengthen and repair high-speed steel tools.
Keywords: Fiber laser, Laser cladding, Ultrafine grained, M2 high-speed steel, Wear resistance