Abstract: Aluminum alloys are susceptible to the Portevin-Le Chatelier (PLC) effect. This phenomenon, particularly well-studied in Al-Mg alloys, is associated with deformation bands that leave unwanted marks on the surface of sheet products after deep drawing, thus restricting their commercial applications. Moreover, the PLC effect is harmful for formability because the PLC bands can lead to a premature onset of necking and fracture.
Heat treatments, performed on Al-Cu alloys to reach the required mechanical properties, influence the PLC effect of those alloys. Actually, Al-Cu alloys can exhibit on their surface unevenness associated with the serrated yielding phenomenon or PLC effect during plastic deformation. Among various experimental approaches to study the aging process, electrical conductivity and acoustic emission are often used. Plastic deformation generates continuous acoustic emission that reaches a maximum at or near the yield stress and decreases with work hardening, due to the motion of dislocations. There is an obvious relationship between the shape of the count rate versus strain rate curve and the microstructure developed in the alloy during aging.
Authors: Fabienne Delaunois, Edwin Denil, Yves Marchal, and Véronique Vitry
Keywords: Aluminum alloys; PLC effect; aging treatments; acoustic emission; electrical conductivity