Portevin-Le Chatelier effect triggered by complex loading paths in an Al–Cu aluminium alloy

Sicong Ren (1) , Thilo F. Morgeneyer (1) , Matthieu Mazière (1) , Samuel Forest (1) , Gilles Rousselier (1)

1 CDM - Centre des Matériaux

Serrated flow has been observed during non monotonic tensile tests of an Al-Cu aluminium alloy in the naturally aged state. The associated propagative localization bands were observed by digital image correlation (DIC). In particular, the Portevin-Le Chatelier (PLC) effect and also Lüders bands were observed in interrupted tests during which the specimen was held for a length of time and also in tests with partial unloading followed by a holding time. Increasing strain rate jumps also triggered the PLC effect. These observations indicate the existence of the PLC effect in this material which was formerly considered insensitive to it at room temperature under monotonic loading conditions. There is no evidence of PLC serrations during constant strain rate tests. A strain ageing finite element model is used that captures the experimentally found PLC triggering effects.

Mots clés: Portevin-Le Chatelier effect; AA2139-T3 aluminium alloy; stress relaxation; strain path change; strain rate sensitivity

Domaines: Matériaux

Sicong Ren, Thilo F. Morgeneyer, Matthieu Mazière, Samuel Forest, Gilles Rousselier. Portevin-Le Chatelier effect triggered by complex loading paths in an Al–Cu aluminium alloy. Philosophical Magazine, 2018, 99, pp.659-678. ⟨10.1080/14786435.2018.1550296⟩. ⟨hal-02003754⟩