Grain scale residual stress response after quasi-static and high strain rate loading in SS316L

High strain rate applications for stainless steels are common, from material processing to ballistics, and residual stresses generated within components during these applications can influence their future performance. Here, high energy x-ray diffraction is employed to examine the development of grain scale residual stress and lattice reorientation under different applied strain rates in an austenitic stainless steel (SS316L). High energy x-ray diffraction was performed before and after loading on specimens deformed at both high and quasi-static strain rates. These measurements show a larger spread in grain averaged residual stresses in the specimen deformed at high strain rate, while the grain averaged reorientation, a metric of plastic strain, was larger in the specimen deformed quasi-statically. Electron backscatter diffraction, employed post-deformation to further investigate the effect of strain rate upon the specimens, found no distinct difference in intragranular misorientation between the two loading conditions. Here it is postulated that the lower deformation rates during the quasi-static test provided more time for crystallographic slip to occur. With greater time, local plasticity through increased, measured lattice reorientation (facilitated by grain boundaries acting as defect sinks) lead to the presence of lower quantities of residual stresses upon unload of the quasi-static test compared to the high strain rate test.