Superplasticity of high-strength Al-based alloys produced by thermomechanical treatment
Superplastic behaviour and the microstructural evolution were investigated.
Alloy with Al3(Sc,Zr) particles and alloy containing Al3Zr and Al3Ni particles.
Alloy with Ni and Zr exhibits a 1.5–2 times finer grains during deformation.
Al3Ni particles provide a larger number of nuclei for recrystallization.
The superplastic properties of two high strength aluminium alloys are investigated. The first alloy contains fine, coherent Al3(Zr,Sc) particles, and the second alloy contains both fine, coherent Al3Zr particles and coarse, eutectic Al3Ni particles. Due to its fine, stable grain structure, the alloy containing both Al3Zr and Al3Ni 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.