Enhanced bonding strength of Al/Fe bimetal by Ni-based alloys Ni-based interlayer prepared by laser cladding technique

In the process of manufacturing aluminum/iron (Al/Fe) bimetal, improving the bonding strength was a crucial consideration. To achieve this goal, this study focused on two aspects: optimizing the composition of intermetallic compounds and modifying the stress state near the interface. The introduction of a Ni-based coating was investigated to accomplish these objectives. The incorporation of the Ni-based coating resulted in a transformation of the phase composition in the reaction layer from the brittle Al-Fe-Si phase to the mechanically superior Al-Fe-Ni phase. Furthermore, significant changes in the morphology of the reaction layer were observed, with the formation of blocky intermetallic compounds adjacent to the Al matrix on the continuous intermetallic phase side. These alterations effectively alleviated stress concentration at the interface, leading to an increase in the shear strength from 50.4 MPa to 117.4 MPa. The findings of this study demonstrated the positive role of the Ni-based coating in mitigating stress concentration at the interface and enhancing the bonding strength of the Al/ Fe bimetallic system. By optimizing the phase composition and morphology of the reaction layer, the bonding capability at the interface was significantly improved.