Microstructural characteristics and mechanical properties of the laser cladded TC4+AlSi10Mg composite coating on carbon fiber reinforced plastic surface

Fabricating TC4 coatings on the carbon fiber reinforced plastic (CFRP) substrate surface will contribute to increasing the applicability of CFRP materials in the aerospace industry. However, chemical metallurgical bonding between the TC4 alloy and CFRP is crucial during the manufacturing process. Here, we studied the effect of Al powder content on the microstructural characteristics and mechanical properties of the laser cladded TC4+AlSi10Mg composite coating on the CFRP surface. Furthermore, the relationship between laser process parameters, interfacial morphologies, and mechanical properties is established. The amount of CFRP decomposed increases with a rise in the AlSi10Mg powder content, while augmenting the penetration of the transition layer into the CFRP material. Moreover, the TC4 coating with 10wt.% AlSi10Mg is composed of α′ martensite, TiC, Ti3Al, and Ti3AlC. The average nano-hardness of the TC4 coating increases from 6.00 to 6.86 GPa when the AlSi10Mg content rises from 5% to 20%. Meanwhile, the maximum shear strength of the CFRP/TC4 interface is 26.8 MPa. Based on the experimental observations and theoretical analysis, the interface reaction mechanism of the laser cladded TC4+AlSi10Mg composite coating on the CFRP surface is: Ti(s)+C(s)→TiC(s), Al(1)+3Ti(s)→Ti3Al(s).