Work hardening and Portevin-Le Chatelier (PLC) effect in aluminium alloys

Abstract

Mechanical testing and microstructure characterization of an AA5182 alloy is performed for use as input for calibration and further development of models for work hardening and dynamic strain aging effects. The experimental conditions for serrated yielding and negative strain rate sensitivity (SRS) are investigated by tensile testing at various strain rates and temperatures. Microstructure, texture and grain size are investigated by use of SEM. Standard tensile tests with Digital Image Correlation (DIC) at room temperature and up to $\SI{150}{\celsius}$ are performed, with strain rates from \num{1e-4} to \num{1}. Under certain regimes of strain rate and temperature, the Portevin-Le Chatelier (PLC) effect can cause unwanted appearances and properties of some dilute alloys under forming operations. Increased understanding of the micro- to macro-scale processes causing the phenomenon, and the use of modeling can help predict occurrence of the Portevin-Le Chatelier effect so that forming processes can be planned as to avoid problems. Standard tensile testing with DIC have been performed, and the mechanical properties for various strain rates have been mapped. Fracture surfaces have been studied in SEM, and the texture analyzed by OIM (SEM-EBSD). An overview of experimental findings are presented.