The influence of temperature on the PLC effect in Al-Mg alloy

Abstract

An experimental investigation of the influence of temperature on the Portevin-Le Chatelier (PLC) effect in Al-Mg alloy is conducted. Under a certain strain rate, the PLC effect is present in the temperature range of 223–328 K. The serration amplitude increases monotonically with increasing temperature, whereas the behaviors of the serration period and the critical strain with temperature include a descending branch under corresponding low temperature range and an ascending branch under corresponding high temperature range. The analysis in relation with dynamic strain aging (DSA) indicates that the temperature plays an important role in the PLC effect by dictating the solubility and the diffusibility of solute atoms. Both the concentration and the diffusibility of solute atoms contribute to increasing the serration amplitude. Under the descending branch temperature range, the serration period mainly depends on the preparation phase and the dominant factor of critical strain is the velocity of dislocations. However, under the ascending branch temperature range, the serration period mainly depends on the pinning phase and the dominant factor of critical strain is the applied stress required for unpinning.