Study on unsteady rolling cooperative deformation and interface behavior of Ti2AlNb/7075Al laminated metal composites

Ti₂AlNb/7075Al laminated metal composites (LMCs) exhibit a low density, high strength, and outstanding mechanical properties under short-term elevated temperatures. They hold significant potential for application in aircraft operating across wide temperature range. However, the significant differences in mechanical properties and processing temperature between 7075Al and Ti₂AlNb present challenges for fabricating LMCs using conventional manufacturing methods. Therefore, this study proposes an unsteady rolling method for fabricating the high-quality Ti₂AlNb/7075Al LMCs. The interfacial bonding rate reaches 88 %. These LMCs with a density of 3 g/cm³ demonstrate excellent mechanical properties, achieving a tensile strength exceeding 650 MPa and an elongation greater than 16 %. Precise strength matching between Ti₂AlNb and 7075Al is achieved during unsteady heat treatment at 650–700 °C for 1–3 min. Within this range, 7075Al shows no signs of over-burning and its tensile strength decreases by only 25 %. Meanwhile, Ti₂AlNb does not experience hardening caused by O-phase precipitation and demonstrates excellent plasticity. This excellent mechanical property matching results in coordinated deformation of the two metals during the rolling process. A few Ti₂AlNb grains undergo kinking to accommodate the deformation. The Ti₂AlNb layer near the interface forms shallow rectangular tear gaps, which are filled by 7075Al, creating a strong mechanical interlocking. Meanwhile, the rapid rolling process prevents the formation of brittle products at the interface. Atomic scale bonding is observed at the interface of the Ti₂AlNb/7075Al LMCs.