Interface bonding behavior and strengthening-failure analysis of 2219 aluminum alloy joint produced by vacuum hot-compression bonding

Vacuum hot-compression bonding (VHCB) has emerged as a promising method for fabricating critical structural components, offering a viable alternative to traditional heavy forging manufacturing. To verify the feasibility and applicability of VHCB in aluminum alloys, a comprehensive study was conducted on the interfacial bonding behavior of 2219 aluminum alloy joints at various temperatures and holding times. The strengthening-failure mechanism of the joints was explored. The results showed that increasing the bonding temperature and holding time enhanced the interfacial bonding quality by promoting void closure, interfacial grain boundary migration (IGBM), and dissolution of interfacial oxides. The joint bonded at 540 °C-30 %-6 h achieved metallurgical bonding by IGBM and dynamic recrystallization (DRX). The initial straight interface was occupied by interfacial fine grains and bulged grain boundaries. The interfacial oxides were transformed into the MgAl₂O₄ phase. Both dislocation strengthening and the interface strengthening collaboratively promoted the strong bonding of the joint. Tensile results indicated that the joint exhibited a yield strength of 127.4 MPa and an ultimate tensile strength of 246.3 MPa, reflecting increases of 31.9 MPa and 39.4 MPa compared to the base material. The joint cracked at a distance of about 300 μm from the bonding interface, and the crack exhibited a wavy fracture along the interface. These findings provide practical guidelines for applying VHCB technology in the fabrication of 2219 aluminum alloy components.