Journal of Materials Research and Technology (Jan 2022)
Effect of annealing and cold rolling on interface microstructure and properties of Ti/Al/Cu clad sheet fabricated by horizontal twin-roll casting
Abstract
In this study, a Ti/Al/Cu three-layer clad sheet was fabricated using horizontal twin-roll casting (HTRC) technology. The interfacial morphology, interfacial microstructure and phases, interfacial bonding strength, micro-hardness, and tensile properties of the clad sheet under different annealing and cold rolling conditions were investigated. The surface morphology of the titanium, copper and aluminum sheets after peeling was observed. Compared with the traditional compounding process, the cast-rolling bonding process can realize the direct combination of molten metal and solid metal strip and achieve higher bonding strength. In the as-cast sheet, the thickness of the diffusion layer is 3.6 μm and the average peel strength (APS) is 20.2 N/mm at the Ti/Al interface, meanwhile the values at the Cu/Al interface are 3.2 μm and 13.8 N/mm. Before the formation of intermetallic compound (IMC) at the interface, increasing annealing temperature can improve the bonding strength by promoting atomic interdiffusion. Further cold rolling can also improve the bonding strength by forming a wavelike interface. Under the action of huge rolling force, the matrices that were not well bonded in the cast-rolling process are contacted at the atomic scale, and as a result new bonding regions are created. By improving the interfacial bonding strength, appropriate annealing and cold rolling processes make the deformation of clad sheet more cooperative. According to the results obtained in this study, the best subsequent processing technology for Ti/Al/Cu clad sheet fabricated by HTRC is annealing at 300 °C for 1.5 h followed by a single pass cold rolling with 40% reduction.
