The effect of pre-strain on tensile behaviour of 316L austenitic stainless steel was investigated, focusing on strain rate sensitivity, temperature sensitivity and strain hardening. Experimental data showed that strain rate sensitivity, temperature sensitivity and strain hardening were weakening with pre-strain. Meanwhile, the variation of microstructure with pre-strain was observed by optical microscopy, scanning electronic microscopy and X-ray diffraction. Then, the mechanical properties of pre-strained material were correlated with the increase in dislocation density and mechanical twinning with pre-strain. Finally, an improved Arrhenius-PS model considering the effect of pre-strain was developed. This paper is part of a thematic issue on Nuclear Materials.

The stress state has an important effect on the deformation and failure of metals. While the stress states of the axisymmetric notched bars specimens are studied in the literature, the studies on the flat metal specimen with inclined notch are very limited and the stress state is not clearly characterized in them. In this paper, digital image correlation and finite element simulations are used to study the distribution of strain and stress state, that is stress triaxiality and Lode angle parameter. Flat specimen with inclined notch was tested to extract the full field strain evolution and calculate stress state parameters at three locations: specimen centre, notch root and failure starting point. It is found that compared with the centre point and the notch root, the failure initiation point can better characterize the influence of the notch angle on the strain evolution. Conversely, the centre point can more clearly characterize the effect of the notch angle on stress state, since the stress states at the failure point and the notch root change greatly during the plastic deformation. Then the calculated stress state parameters of the flat metal specimen with inclined notch at the centre point are used in Wierzbicki stress state diagram to establish a relationship between failure mode and stress state.