High-Temperature Plastic Deformation and Acoustic Emission of Aluminum in a Low-Stability State

It is found out that under conditions of high-temperature mechanical loading of aluminum in a low-stability state, deformation is manifested as discrete macroscopic changes. An analysis of the activation energy of the temperature-dependent deformation and acoustic emission demonstrates that the period of deformation buildup is accompanied by the diffusion-controlled processes, giving rise to a stepwise accumulation of deformation and quasi-periodic transmission of high-amplitude acoustic-emission signals. The activation volume of an elementary deformation event is increasing exponentially with temperature, indicating an increased scale level of cooperative atomic displacements and formation of a local low-stability state or crystal-lattice instability. The macroscopic manifestation of the sharp deformation change (jump) serves as an evidence of correlation between the elementary events of deformation.