Abstract
The effect of grain size on strain hardening of magnesium alloy AS21X was investigated by room temperature tensile tests with concurrent in-situ acoustic emission (AE) measurements. Material was prepared by high-pressure die casting and direct squeeze casting resulting in two different microstructures, fine and coarse grained ones, respectively. The strain hardening rate was determined, along with the AE count rate, as a function of stress and strain. The different microstructures showed distinct strain hardening behaviour. The coarse grained material exhibited a tensile curve with parabolic shape, whereas the fine grained material had a marked yield plateau.

Key words
magnesium alloys, plastic deformation, acoustic methods, tension test

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