Abstract
The in-plane tensile behaviour of rolled sheets of the magnesium alloy AZ31 was investigated in both an H24 state and an aged state. Whereas the very high initial strain-hardening rate decreases monotonically with strain for the H24 samples, the annealed structure exhibits a striking increase in the strain-hardening rate. To explain this phenomenon, the occurrence of sessile dislocations associated with a secondary (pyramidal) slip is proposed. The absence of increasing hardening for the H24 state is supposed to be related to higher yield stresses (predeformations) within the grains of the polycrystalline aggregate.
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