Experimental approach of a crystallographic cleavage criterion in a cast aged duplex stainless steel

Abstract The stress state distribution in an aged duplex steel is determined in each phase and is then correlated to local damage mechanisms. The measurements are performed at the grain scale because the studied material contains coarse grains up to one millimetre in size. A single-crystal specific X-ray method is required to determine the stress tensor. During in situ loading, the mechanical state determined in the ferritic crystal is associated with both the plastic flow and the damage mechanism observation. The coupling of the techniques makes it possible to establish that for the studied aged material, the stress normal to a {100} plane value of 465 MPa can be considered as a crystallographic criterion for cleavage propagation. The comparison of this value with the Cottrell's model seems to be good but the number of dislocations in the pile-up must be verified experimentally.