Hot compression bonding behavior and constitutive model of spray deposited 2195 Al-Cu-Li alloy

Hot compression bonding (HCB) tests of spray deposited 2195 Al-Cu-Li alloy were carried out under different temperatures and strain rates when the sample chamber was vacuumized to 1.0 x 10-3 Torr. The constitutive models and processing map during HCB process were established, and interfacial microstructure, especially the oxide film evolution and bonding mechanism of this alloy were investigated. The results showed that this alloy possesses both good bondability and stable deformation ability in three deformation parameter regions, with a temperature of 500 degrees C and strain rates of 0.01-0.05s- 1 and 1-10s- 1, and temperature of 430-470 degrees C and strain rate of 0.05-0.55 s-1. The interface of this alloy forms oxide film even under near vacuum environment, and the oxide films are predominantly amorphous Al2O3 and nanocrystalline of gamma-Al2O3, and a small amount of Li2CO3, Al(OH)3, MgAl2O4. The strain rate influences bonding mechanism dramatically, when samples are compressed at high strain rate, the interfacial healing was highly dependent on microplastic deformation and mechanical interlock around the interface. While compressed at low strain rate, the interfacial healing was mainly dependent on grain boundary bulging or particle-stimulated nucleation, grain boundary migration and dynamic recrys-tallization (DRX).