Deformation effects and acoustic emission during high-temperature straining of aluminum

Thermomechanical cycling in polycrystalline aluminum has been studied. It is established that a monotonic accumulation of deformation with increasing temperature or mechanical stress during a cycle can change to a macroscopic deformation jump, which is accompanied by the transition from a monotonic acoustic emission into separate acoustic signals. In this state, the activation volume of an elementary deformation event exhibits exponential growth with the temperature during the cycle, which is evidence for an increase in the extent of elementary atomic displacements involved in this event.