Stade I d’endommagement par fatigue plastique oligocyclique (FPO) dans un acier inoxydable duplex (AID)*

A. EL BARTALI; M.C. MARINELLI; M. BALBI; V. AUBIN; I. ALVAREZ-ARMAS; S. DEGALLAIX-MOREUIL

Matériaux & Techniques

EDP Sciences

Año: 2012 vol. 100 p. 69 - 78

0032-6895

The cyclic plastic activity and the initiation and propagation of the first microcracks in a forged austenitic-ferritic stainless steel under low-cycle fatigue at room temperature are studied from a priori EBSD measurements, CCD camera observations in situ during the mechanical test and a posteriori SEM observations. The existence or non-existence of type Kurdjumov-Sachs crystallographic orientation relations between phases is analysed. The activated slip systems in numerous alpha and gamma grains and the slip transmission conditions between phases are identified. The Schmid factor influence is shown to be different in the austenite and in the ferrite. The initiation and the propagation of the microcracks are analysed, and the conditions of the surface microcrack propagation through the microstructure.