A new method to quantify the Portevin-Le Chatelier instabilities: application to aluminium-lithium alloys

The use of a new method of double strain measurement makes it possible to quantify the macroscopic aspects of the Portevin-Le Chatelier instabilities which appear with some AlLi alloys and particularly with the former version of the industrial 2091 alloy. Among other parameters, a strain localization ratio which may reach values up to 180 is defined. The results obtained suggest a possible explanation of the decrease in toughness with ageing time of the former version of the industrial 2091 alloy.