| According to this research, Fe-based amorphous alloy coating (containing W,Cr,Mo,Ni,Si,B) was prepared by air plasma spraying(APS) technique firstly, then alloyed zone with high density and crack-free was deposited by laser remelting craft on coatings with different porosity but same thickness (300μm). The remelting craft was optimized. The organization structures and properties of the remelting zone were investigated by means of Microhardness Tester, Optical Microscope (OM), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Disperse Spectroscopy (EDS).The correlations between laser remelting parameters and the performance of oriented in microhardness and the height of alloyed zone were studied. Based on the orthogonal test, the optimized parameters were obtained: coating with the lowest porosity, laser power:700W, scanning velocity:4mm/s, spot diameter: 3mm. remelting zone with moderate dilution ratio, artistic appearance was achieved, whose height is 233.9μm,which got a firm combination with substrate coatings.The original coating experienced the process to melt in high temperature and solidification contraction in rapid rate of cooling under the high laser power density,as well as the heat treatment process in multi-channel overlapping remelting, which eliminated the flat granule joining structure, and formed the compact molten alloy zone. The molten pool was the model organization structure of rapid cooling. A luminous has formed in joining zone between molten pool and substrate, because of the great gradient of temperature; Crystals near the belt place grew up fast to the bulky dendritic appearance with epitaxial growth, In the middle and upside of the alloy zone, they were net structure and honeycomb-shaped organization separately.Through the phase analysis of XRD and elementary analysis of EDS, the alloy zone organization was transformed from the amorphous phase of coating to the crystallization completely, which is complex heterogeneous structure. There areα-Fe retained in the coating, the new production cubic system [Fe, Ni] sosoloid, phase Ni- Cr-Fe, as well as Fe2Si, Fe3.5B, and Fe2W.After the determination, compared with microhardness of amorphous coating before remelting, single channel alloy zone does not have the remarkable change. Obviously, there is a negative correlation between the hardness of single channel remelting alloy zone and degree of the substrate dilution ratio. The higher the dilution ratio is, the lower hardness of alloy zone is.During multi-channel remelting, due to the thermal reaction influence, the second path heat treatment causes the grain in first path refining The hardness of the first path elevated to 870HV0.1, whereas the second path has slightly the dropped to 720HV0.1 as a result of the substrate dilution function. But along with the heating effect of the third path, the microhardness of the second has rised.Therefore, remelting alloy zone with higher microhardness than the sprayed coating lead a widespread practical application significance to mass production.
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