Damage in Aged Austenoferritic Alloys

Multiphase materials often develop internal stresses during straining [1,2]. Austenoferritic duplex steels, made of hard and soft phases with similar volume fractions, are therefore liable to develop such stresses. In addition, the bipercolated topology of the phases can yield a more difficult relaxation of these stresses, which can be at the origin of damage and failure. It is then of interest to investigate the evolution of internal stresses and their occasional relaxation during straining. For this reason, we performed Bauschinger tests in order to characterise internal stresses [3,4,5] and their possible relaxation at the macroscopic scale, and Transmission Electron Microscopy (TEM) in situ tensile tests to identify the related microscopic relaxation mechanisms.