Microstructural characteristics and property of laser cladded TC4+AlSi10Mg composite coating on the CFRP surface

TC4+AlSi10Mg composite coating was successfully prepared on the surface of carbon fiber reinforced plastics (CFRP) by laser cladding technology. Microstructure, elemental composition and distribution as well as phase composition of the interface layer between the TC4+AlSi10Mg composite coating and CFRP substrate were analyzed by scanning electron microscopy, energy disperse spectroscopy, and transmission electron microscopy. Hardness was measured by nanoindentor along the vertical direction from the composite coating to the CFRP substrate. Research findings showed that laser cladding technology could be applied to fabricate uniform and continuous TC4 coating on the surface of CFRP substrate. Upon the heat effect of laser cladding, the TC4+AlSi10Mg composite powder melted and then penetrated into the interior of the CFRP substrate, thus achieving a good metallurgical bonding. Finally, a continuous interface layer formed among carbon fiber, plastics, and composite coating. The interface layer between the TC4+AlSi10Mg composite coating and CFRP substrate was mainly composed of TiC, Ti₃Al, TiS₂, and Ti₃AlC phases. The average hardness of the CFRP substrate was 10.15 HV, while the maximum hardness of the composite coating was 1 914 HV. In addition, based on experimental observation and theoretical analysis, the dominant interface reaction mechanism of the laser cladded TC4+AlSi10Mg composite coating on the CFRP surface can be drawn as follows: Ti(s) + C(s) → TiC(s), Al(1) + 3Ti(s) → Ti₃Al(s).