Microstructure and Properties of 15-5PH Coatings by Laser Cladding on 17-4PH Surfaces for Aviation Applications
The 17-4PH stainless steel is widely used in critical components such as turbine blades in the aerospace industry.To realize the repair and remanufacturing of damaged aerospace components made of 17-4PH,15-5PH coating was prepared on the surface of 17-4PH using laser cladding technology.The phases,microstructure,microhardness,wear resistance,and corrosion resistance of the coating were analyzed.The results show that the coating is mainly composed of Fe-Cr,martensite,and α-Fe phases.The bonding area between the coating and substrate is a planar crystal structure,with columnar grains predominating at the bottom and middle,and a mixture of columnar and a small amount of equiaxed grains at the top.The average microhardness of the coating and substrate is 408.7HV0.5 and 347.5HV0.5,respectively,with an increase in coating hardness of 17.6%.The average friction coefficients of the coating and substrate are 0.3051 and 0.3754,and the wear cross-sectional areas are 813.74 μm2 and 2058.12 μm2,respectively,indicating a significantly improved wear resistance of coating compared to the substrate.The corrosion potentials(Ecorr)of the coating and substrate are-1.0780 V and-1.0975 V,and the corrosion current densities(Icorr)are 1.229×10-3 mA/cm2 and 0.907×10-3 mA/cm2,respectively,demonstrating comparable corrosion resistance.The microstructure and surface properties of the coating suggest that laser cladding with 15-5PH coating can be applied to the repair and remanufacturing of aerospace components made of 17-4PH.
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