Microstructures of laser cladding Co-based Cr-W alloy layer on stainless steel valve

摘要

Investigation has been carried out into the solidification features and formation law of microstructure for laser cladding Co-base Cr-W Alloy Laser on Stainless Steel Valve. It is shown that the microstructure at the cladding layer bottom belongs to typical epitaxial growth on basis of plane, and the dendrite crystal is coarser. The microstructure at the top is the regular pine-tree eutectic crystal, and at the middle is small cell crystal and columnar crystal. The crystalline anisotropy influences the crystal growth form. Grain nucleation has obvious features of heterogeneous nucleation in microstructure of cladding. The results also show that the compositions in microzone of cladding layer are non-uniform, different elements segregate along crystalline axis or interdendritic, and these have resulted in the non-uniform microstructure.