Neutron Diffraction Investigation of Low and High Cycle Fatigue Austenite Stainless Steels

Abstract

A series of samples from low carbon austenite stainless steels X6CrNiTil810 (0.04 wt % C) with different degrees of low- and high-cycle fatigue were studied on the two-axis diffractometer in NPI (Rez) to obtain microstrain characteristics of austenite and martensite produced by plastic deformation during cycling. A stabilization effect of low frequency cycling with respect to the mean square microstrain above 30 %-fatigue is found because practically no evolution of neutron peak broadening was observed in the both phases in the measured samples. A similar stabilization effect after a certain number of cycles was before noted in literature. Processing of the experimental data from high-cycle fatigue samples has found the interesting phenomenon in a behaviour of microstrain in the austenite phase vs the fatigue degree. The remarkable bounce from about 50.10 -6 up to 400.10 -6 has happened after one million cycles. No evolution of microstrain was observed in the martensite phase.