Tensile ductility of several commercial aluminum alloys at elevated temperatures

Abstract

One experimental and five commercial aluminum alloys were tested in tension at elevated temperatures (225 °C to 500 °C) over a range of strain rates (2×10⁻⁵ to 10⁻¹ s⁻¹). The experimental alloy contained 5 wt pct Zn with a balance of Al. The commercial alloys included AA 5182, 5754, 7150, 6111, and 6022. Two 5182 materials were examined, one produced by standard ingot-processing methods and the other by continuous casting. The 5754 and 5182 alloys exhibited a deformation regime consistent with solute-drag creep for values of diffusivity-compensated strain rate less than 10¹³ m⁻². Within this regime, the 5754 and ingot-metallurgy 5182 materials exhibited tensile ductilities up to 140 pct. The continuously cast 5182 material exhibited lower ductility in this regime than the 5754 and ingot-metallurgy 5182 materials, despite similar stress exponents. Ductility was reduced in the continuously cast 5182 because of significant dynamic grain growth and cavitation. The 7150, Al-5Zn, 6111, and 6022 materials exhibited significantly higher stress exponents and lower tensile ductilities than the 5000-series materials.