关键词: 铝/钢双金属, 液-固复合铸造, 热浸镀, 界面扩散, 显微组织, 力学性能

Abstract: Aluminium/steel bimetallic composites were prepared with pure aluminium and 304 stainless steel by liquid-solid composite casting, and effects of hot-dipping time (1, 3, 5, 10 min) of the steel in pure aluminium melt on the interface microstructure and mechanical properties of aluminium/steel bimetallic composites were investigated by scanning electron microscope and universal tensile testing machine. The results show that the aluminium/steel bimetallic compositing is a process of dissolution to form an interface and then diffuse within each other to make the interface grow, and the thickness of the diffusion layer increases gradually with the hot-dipping time. The thickness of the diffusion layer is about 19.7 μm for 3 min hot-dipping. After 10 min hot-dipping, the diffusion layer thickness is about 36.3 μm, increased by about 84.3% than that of hot-dipping for 3 min. The optimum hot-dipping time is 3 min, and the tensile strength of the aluminium/steel composite specimen reaches the maximum value of 21.2 MPa. With the increase of hot-dipping time, the tensile strength shows a tendency of increasing and then decreasing due to the formation of more brittle intermetallic compounds, which generate cracks and lead to reduction of the bonding effect.

Key words: aluminium/steel bimetal, liquid-solid composite casting, hot-dipping, interface diffusion, microstructure, mechanical properties