Dissimilar Joining of Aluminum to High-Melting-Point Alloys by Hot Dipping

In this study, the dissimilar joining of aluminum to high-melting-point alloys, including steel, titanium, and copper, was successfully achieved through hot-dipping. By precisely controlling the dipping temperature at 670 degrees C and maintaining a dipping time of 5 s, uniform aluminum layers with a thickness of 3-4 mm were successfully formed on the surfaces of high-melting-point alloys. This process enabled effective dissimilar metal joining between Al/steel, Al/Ti, and Al/Cu. Metallurgical bonding at the joining interfaces was achieved through the formation of uniform intermetallic compounds, specifically Fe4Al13, TiAl3, Al2Cu, and Al3Cu4, respectively. The different joints exhibited varying mechanical properties: the Al/Cu joint demonstrated the highest shear strength at 79.1 MPa, while the Fe4Al13-containing joint exhibited the highest hardness, reaching 604.4 HV. Numerical simulations revealed that an obvious decrease in interfacial temperature triggered the solidification and growth of the aluminum layer. Additionally, the specific heat and thermal conductivity of the high-melting-point alloys were found to significantly influence the thickness of the aluminum layer. The hot-dip joining technology is well suited for dissimilar metal bonding involving large contact areas and significant differences in melting points.