INFLUENCE OF PORTEVIN-LE CHATELIER EFFECT ON RUPTURE MODE OF ALLOY 718 SPECIMENS

摘要

A set of tensile tests has been carried out under air environment in the temperature range [450°C-700°C] in order to characterize the interactions between oxidation assisted intergranular cracking and Portevin -Le Chatelier effect. It is shown that the occurrence of jerky flow stops the intergranular damaging mechanism. The construction of a Dynamic strain aging-Intergranular fracture-PLC instabilities map is then proposed. The surprising relation between crack initiation disappearance and PLC instabilities of type C in the temperature range explored is discussed. Finally the assumption of the occurrence of such phenomenon at the tip of a propagating crack is addressed.