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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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An extruded magnesium AZ31 magnesium alloy was processed by rotary swaging (RSW) and then deformed by tension and compression at room temperature. The work-hardening behaviour of 1–5 times swaged samples was analysed using Kocks-Mecking plots. Accumulation of dislocations on dislocation obstacles and twin boundaries is the deciding factor for the strain hardening. Profuse twinning in compression seems to be the reason for the higher hardening observed during compression. The main softening mechanism is apparently the cross-slip between the pyramidal planes of the second and first order. A massive twinning observed at the deformation beginning influences the Hall-Petch parameters.

The microstructure and mechanical properties of AZ31 alloy rods are investigated after rotary swaging in five successive steps. The microstructure is analyzed using light microscopy and electron backscattered diffraction. Swaged samples exhibit refined microstructure. Tensile and compression tests are conducted at room temperature. The yield stress and the ultimate stress are determined. Acoustic emission is measured in situ during straining. Deformation mechanisms are closely linked to twinning and dislocation slip in non‐basal planes.

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