A BI-PHASED POLYCRYSTALLINE MODEL FOR THE CYCLIC SOFTENING OF A DUPLEX STAINLESS STEEL IN UNIAXIAL AND BIAXIAL CYCLIC LOADING

P EVRARD; V AUBIN; S DEGALLAIX; D KONDO; I ALVAREZ

Berlin

Conferencia; 6th International Conference on Low Cycle Fatigue; 2008

Deutsch Verband fur Metalkunde DVM

In this paper, an extension of the bi-phased polycrystalline model in [1] is proposed in order to simulate the cyclic softening observed in an austenitic-ferritic stainless steel under uniaxial and non-proportional biaxial cyclic loading [2]. Assuming that the cyclic softening for uniaxial and biaxial non-proportional cyclic loading is due to a rearrangement of dislocations in hard (rich in dislocations) and soft (poor in dislocations) zones in ferritic grains, the ferritic single crystal law is modified. The new model parameters are identified from TEM observations and by inverse procedure. Finally, the new model is validated for other cyclic loading paths. A good agreement is observed between simulation and experimental data.