Specimens taken in the extrusion direction were symmetrically low cyclic loaded at a constant strain rate of 10-3 s-1 and at various stress amplitude of sigma = (150, 195, 250) MPa in respect to the macroscopic tensile and compresive yield strength. The acoustic emission parameter was correlated with stress-time curves to study of deformation mechanisms.
Very high acoustic emission activity in the compression half cycle indicates the activation of twins. In the second and following tensile half cycles, detwinning process was observed.