Fatigue behaviour of hot pressed austenitic TWIP steel and TWIP steel/Mg-PSZ composite materials

This research work presents the fatigue behaviour of a high-alloyed austenitic TWIP steel as well as metal matrix composites based on this steel grade as matrix material and MgO partially stabilized zirconia (Mg-PSZ) as reinforcing phase. The specimens were produced using the hot pressing technique. The unreinforced steel and MMCs containing 5 and 10 vol.% Mg-PSZ were investigated under total strain control in order to clarify the influence of the ceramic reinforcement. The cyclic deformation behaviour in terms of cyclic softening and/or cyclic hardening as well as fatigue lives of the different materials are discussed. Microstructures were examined to study the deformation and dislocation structures as well as phase transformations using electron channelling contrast imaging (ECCI) and electron backscatter diffraction (EBSD), respectively.