Affiliations: LM3, ENSAM Paris, ESA CNRS 8006, 151 bd de I’Hôpital, 75013 Paris, France | LPMM, ENSAM Metz, UMR CNRS 7554, 4 av. Augustin Fresnel, 57078 Metz Cedex 3, France | ED6 Département MTC, Route de Sens, 77250 Morêt sur Loing, France
Note: [] Corresponding author.
Abstract: Polycrystalline approaches are more and more used to characterise the mechanical behaviour of material with the interest to take into account the mechanical properties of the material constituents. In this case, for a better understanding of the polycrystalline material mechanical response, mesoscopic and microscopic parameters must be clearly identified. Our purpose is also to characterise the mechanical behaviour of a cast duplex stainless steel, containing 30% ferrite and 70% austenite, using X-ray diffraction. The mechanical state can be determined using X-ray diffraction technique which enables to measure strains in each phase separately. The measurements are performed at the grain scale because the studied material exhibits coarse grains of up to one millimetre. In this case, only few crystals are irradiated by the incident X-ray beam and the classical sin2 Ψ method for stress determination cannot be applied to this material. An adaptation of the single crystal measurement method to large grains materials is used. Stresses so determined correspond to second order stresses. The measurement in each phase has successfully been applied to follow the stress state evolution during an in situ tensile test. Several grains, with different crystallographic orientations were studied. For each one, the stress tensor was determined in the two phases under different macroscopic loading in elastic and plastic domains. A modelling of the mechanical single crystal behaviour is developed and our purpose is to identify the parameters of the single crystal behaviour law using X-ray single crystal stress analysis during in situ tensile test.
Keywords: X-ray diffraction, Second order stresses, Cast duplex stainless steel, Mechanical behaviour
