Microstructural Evolution of AA5052 Alloy Sheets in High-Speed Rolling

Abstract

It is known that grain refinement improves balance of strength and ductility of materials. As a technique to obtain fine-grained microstructure, dynamic recrystallization can be used in industrial processes. The authors reported that fine grains appear beneath the surface of Al-Mg alloy sheet by high-speed rolling. In this study, rolling conditions to form fine recrystallized microstructure were investigated. AA5052 alloy sheets were rolled at 500 m/min, 1000 m/min or 2000 m/min with thickness reduction of 30%, 50% or 70% at 473 K, 523 K, 573 K or 623 K. After the rolling, the sheets were water-quenched immediately. It is found that the critical strain for dynamic recrystallization is very large. For example, when the sheets are rolled at 1000 m/min and 623 K, thickness reduction greater than 76% is required for dynamic recrystallization.