Grain size and microhardness evolution during annealing of a magnesium alloy processed by high-pressure torsion

Abstract

High-pressure torsion (HPT) was used to impose severe plastic deformation on a magnesium alloy AZ31. The material was processed for 0.5, 1, 2, 3, 5 and 7 turns at room temperature under a pressure of 6.0 GPa. Samples were annealed for 1800 s at temperatures of 373 K, 423 K, 473 K, 573 K and 673 K. Microhardness tests and metallography were used to determine the evolution of strength and grain size as a function of the annealing temperature. The results show that recrystallization takes place at temperatures higher than 423 K. The annealing behavior is independent of the number of turns in HPT.

Keywords

• Magnesium alloys
• High-pressure torsion
• Annealing
• Severe plastic deformation