EBSD analysis of low-cycle fatigue damage in Z2CND18.12N austenitic stainless steel

Abstract

Aimed at low-cycle fatigue damage of Z2CND18.12N austenitic stainless steel for nuclear power pipelines，the influences of the acquisition and post-processing parameters on the local misorientation （ML） were studied by electron backscattered diffraction （EBSD） technique. The damage evolution of grains with typical orientations was discussed based on the parameters after optimization. The results show that the step size，filter and binning all affect the value of ML. Taking into account factors such as grain size，testing accuracy， and efficiency，the optimal selection is to determine binning 2×2， filter 11×11， and testing step size of 2 μm or 5 μm，respectively. Two damage regions with different levels are characterized. The peak and average values of ΔML in 〈111〉 orientation are higher than those in 〈101〉 and 〈001〉 orientations，and the values of ΔML in 〈101〉 orientation are the smallest. Large ML is observed in small grains，especially in the grain boundaries and intersections. Meanwhile，non-uniformity of deformation distribution was discussed in according to the effects of grain size and grain boundary. It is confirmed that ML can effectively evaluate the deformation damage of Z2CND18.12N steel，which is valuable for the development of material and structural damage evaluation technology based on multi-physical parameters.

Keywords

• austenitic stainless steel
• fatigue
• ebsd
• crystal orientation
• local misorientation