Use of Heterogenization for Improving Alloy AA5083 Superplasticity Indices

Abstract

The microstructure and superplasticity indices are compared for specimens of alloy AA5083 prepared by two technologies: using intermediate heterogenization annealing and without it. As a result of heterogenization β -phase is separated that during recrystallization stimulates new grain growth, and therefore the grain size within specimens is smaller by almost a factor of two than for specimens not subjected to annealing. Use of heterogenization annealing provides a relative elongation up to 650% at 550°C and a constant strain rate of 1·10⁻³ sec⁻¹, and lower residual porosity. Sheet prepared by this technology makes it possible to increase forming rate by several factors.