INVESTIGATION OF THE PORTEVIN-LE CHATELIER EFFECT IN AlMg ALLOYS: EFFECT OF TESTING RATE

Abstract

The study investigates the Portevin–Le Chatelier (PLC) effect in the cold-rolled Al-Mg alloy EN AW-5754. The tensile tests were performed on dog bone specimens at test speeds of 10, 20, and 50 mm/min. Digital image correlation (DIC) and infrared thermography were used to monitor strain rate and temperature changes. The results showed a strong correlation between PLC line propagation, strain rate variations, and temperature changes. Regardless of the test speed, the characteristic jagged shape of the material was observed due to the PLC effect. As the deformation progressed, both the strain rate and the temperature increased, with the changes being more pronounced at higher test speeds. DIC and infrared images show that temperature peaks correspond to moments of increased plastic deformation and sudden drops in strain rate. The formation of overlapping PLC lines also showed the random and unpredictable nature of the phenomenon.

Keywords

• AlMg alloy
• Portevin-Le Chatelier effect
• testing rate
• Digital Image Correlation (DIC)