Superplasticity of high-strength Al-based alloys produced by thermomechanical treatment.

The superplastic properties of two high strength aluminium alloys are investigated. The first alloy contains fine, coherent Al 3 (Zr,Sc) particles, and the second alloy contains both fine, coherent Al 3 Zr particles and coarse, eutectic Al 3 Ni particles. Due to its fine, stable grain structure, the alloy containing both Al 3 Zr and Al 3 Ni particles exhibits significantly better superplastic properties. The superplastic behaviour in tension under both constant and initial strain rates was compared, and the effective activation energy of superplastic deformation was calculated. The alloy containing both fine and coarse particles exhibit 1100%–1200% elongation at strain rates of 1 × 10 −2 s −1 –1 × 10 −1 s −1 and temperature of 440 °C. [ABSTRACT FROM AUTHOR]