Microstructure evolution and fatigue behavior of 2124 aluminum processed by ECAE with back pressure

Microstructure evolution, workability, and post-working fatigue behavior were established for aluminum alloy 2124-T851 processed via equal channel angular extrusion (ECAE) with back pressure. ECAE without back pressure resulted in complete fracture during the first pass. On the other hand, ECAE with back pressure enabled the production of sound material with significant grain refinement to the nano-scale. In contrast to typical property trends, an attractive combination of tensile ductility and LCF fatigue life was obtained as well as improved strength and HCF fatigue life compared to coarse-grained material in the as-received (T851) condition.