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The work focuses on experimental examination of the fatigue behavior of magnesium alloy AZ31 produced by three different procedures: squeeze casting (SC), hot rolling (HR), and equalchannel angular pressing (ECAP). The microstructures produced were studied by light and transmission electron microscopy (TEM). Squeeze-cast AZ31 had low porosity and coarse grains, while hot-rolled material showed microstructure with grain size of 3 to 20 lm. The finest grain structure with the average grain size of about 1 to 2 lm was found in the material pressed 4 times at 200°C using the ECAP technique, route B c . It was shown that low-and high-cycle fatigue behavior under symmetric loading at room temperature and with loading frequency of 20 Hz is strongly dependent on the technique employed in producing the alloy. The ECAP was shown to improve the fatigue life of the material in the low-cycle region over that of the squeezecast material. However, the fatigue life of AZ31 after ECAP was slightly lower than that of the hot-rolled material. In the high-cycle region, the hot-rolled material and the material that underwent ECAP exhibit the same fatigue strength, which is superior to that of the squeeze-cast alloy. Fatigue crack initiation and the character of fracture were examined by means of scanning electron microscopy.

International audienceScaling behavior is found in acoustic-emission events associated with stress drops observed in velocity-driven plastic deformation of an Al alloy, which exhibits jerky plastic flow. The occurrence of scaling proves that these acoustic-emission events, which are commonly regarded as “elementary” ones, have a small-scale self-organized structure comprising a group of peaks correlated in time. This structure reveals details of the temporal variation in elementary plastic events at a microsecond scale, which are hardly accessible by other measurement techniques

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