Influence of Annealing Time on the Microstructure and Mechanical Properties of Multilayer Ti/Al Clad Plates Produced via Vacuum Rolling

Abstract

Ti/Al clad plates combine several beneficial properties, including low cost, light weight, and high strength. However, these materials encounter issues, such as poor deformation compatibility and high susceptibility to oxidation, leading to weak interfacial bonding. In this study, multilayer Ti/Al clad plates were fabricated via vacuum rolling, producing oxidation-free and clean interfaces. The symmetric billet design facilitated the coordination of the Ti and Al deformation, which resulted in an ideal structure. The diffusion layers of Ti and Al were observed at the rolled Ti/Al composite interface, while there was no obvious diffusion of Si and no formation of Al₃Ti. The Ti/Al clad plate after rolling exhibited an ultimate tensile strength (UTS) of ~ 290 MPa and an elongation of ~ 13.6%. After 3 h of annealing, fine Al₃Ti particles were detected at the interface. After 6 h of annealing, a continuous and dense Al₃Ti layer with a thickness of approximately 0.954 μm was formed, which significantly enhanced the tensile properties (UTS of ~ 323 MPa and elongation of ~ 22.8%). After 15 h of annealing, the Al₃Ti layer increased to ~ 3.5 μm, illustrating the effect of annealing time on interfacial layer growth. Meanwhile, the width of the interfacial Si diffusion zone also gradually increased with prolonged annealing. These findings highlight the importance of controlling the intermetallic layer thickness to achieve an optimal balance between UTS and elongation in Ti/Al clad plates.

Graphical Abstract