Evolution of Microstructure, Mechanical Properties, and Thermal Conductivity of an Al-Li-Cu-Mg-Zr Alloy Processed by Accumulative Roll Bonding (ARB)

Abstract

Al-Li-Cu-Mg-Zr alloy was processed by accumulative roll bonding (ARB). The microstructure, mechanical properties, and thermal conductivity were investigated. With increasing number of ARB cycles, the microstructure was refined and the processed strips exhibited metallurgical bonding. During ARB processing, the tensile strength was enhanced while the elongation remained in a stable range. The sample after two cycles showed the best comprehensive combination of strain hardening, grain refinement, and high bonding quality, resulting in tensile strength, elongation, bending strength, and thermal conductivity of 322.34 MPa, 17.84%, 528.67 MPa, and 202.26 W/m K, respectively. Further increasing the rolling cycles weakened the investigated properties of the studied alloy. With increasing number of ARB cycles, the tensile fracture morphology revealed that the average dimple size steadily decreased, causing a change in the fracture type from ductile to mixed ductile–shear. The obtained ARB-processed samples resisted greater bending deformation with no damage or interfacial delamination.