Improved Combination of Strength and Ductility in Zirconium-Added Al-Zn-Mg-Cu Alloy Processed with High-Pressure Torsion

Abstract

To realize high-strength and high-ductility aluminum alloys, an Al-Zn-Mg-Cu-based alloy was produced by high-pressure torsion (HPT) processing. The chromium in the alloy was replaced with zirconium, and the iron content of the alloy was decreased to avoid ductility loss due to iron-containing intermetallic compounds formed during crystallization. The microstructures and mechanical properties of the processed alloy were investigated. The grains were elongated perpendicular to the rotation axis. The elongation of the alloy containing chromium decreased with increasing number of turns. In the case of the alloy in which chromium was replaced with zirconium, the strength increased with increasing number of turns, without reducing the elongation. The alloy exhibited an ultimate tensile strength of 929 MPa and an elongation of 6.4%.