Influence of the strain rate on the plc effect and acoustic emission in single crystals of the CuZn30 alloy compressed at an elevated temperature

The purpose of these investigations was to determine the effect of the strain rate on the phenomenon of a heterogeneous plastic deformation of the Portevin-Le Chatelier type while testing free compression of CuZn30 single crystals with a crystallographic orientation of [139] at 300 °C. Moreover, the relations between the work-hardening curve σ-ε displaying the PLC effect and the characteristics of the signals of the acoustic emission generated in the uniaxial-compression test were determined. It was found that the process of plastic deformation of the tested single crystals in the analyzed range of the frequencies up to 35 kHz generates differentiated sources of acoustic-energy emission, mainly the impulsive emission generated by signal events, correlated with the oscillations of the stresses on the work-hardening curves σ-ε. The strain rate mainly causes the changes in the intensity of the oscillation typical for the PLC effect.