D-53 CHANGES IN ELASTIC STRAIN PROFILES AROUND A CRACK TIP DURING TENSILE LOADING AND UNLOADING CYCLES
The changes in elastic lattice strain profiles and plastic zone around the fatigue crack in a compact-tension (CT) specimen were investigated during monotonic tensile loading and unloading cycles using neutron diffraction. The CT specimen, made of an austenitic 316 stainless steel, was fatigue pre-cracked under load control with a maximum applied load of 6667N. Spatially-resolved strain measurements were performed to determine the inplane (parallel to the loading direction) and
... nd through-thickness (perpendicular to the loading direction) lattice strain profiles ahead of the crack tip under a constant tensile load using SMARTS instrument at the Los Alamos Neutron Science Center. The strain scanning was repeated under various applied loads ranging from 667 to 8889 N. The results will be discussed in the context of the changes in the crystallographic elastic/plastic anisotropy (e.g., behavior of plastically-deforming and load-bearing orientations) and geometrical anisotropy (i.e., in-plane and through-thickness behavior) as functions of the distance from the crack tip and the applied load. The results will provide a basis for better understanding of the micro-mechanics around the crack tip during fatigue deformation.