Damage and rupture mechanisms in an austenoferritic duplex steel

The influence of ageing on damage and rupture mechanisms in an austenoferritic duplex stainless steel is studied using conventional straining and impact toughness testing at 20°C and 320°C, and in situ SEM straining at 20°C. While the as-received alloy fails in a ductile mode, damage in the aged material starts with cleavage nucleation in ferrite. We show that, owing to the bipercolated topology of the alloy, these cleavage cracks can propagate …