Stability of austenitic 316L steel against martensite formation during cyclic straining

Abstract

Solution-annealed AISI 316L steel was fatigued with constant plastic strain amplitudes at room temperature and under various conditions at depressed temperatures down to 113 K to reveal its stability against deformation-induced martensite formation. Microstructural changes induced by fatigue were characterized by transmission electron microscopy (TEM), electron channeling contrast imaging (ECCI) and electron backscattering diffraction (EBSD) techniques. Neutron diffraction and magnetic induction method were adopted for quantification of martensite content. Deformation-induced martensite formation in the bulk of material was evidenced for low temperature cyclic straining under various conditions. Room temperature cycling, even with high plastic strain amplitudes, results in a local very limited martensite formation in areas closely linked with the long fatigue crack growth.