PNNL

Abstract

The influence of strain rate on development of deformation texture under a dynamic shock compression of a 904L stainless steel was quantitatively investigated using synchrotron X-ray diffraction and crystallographic orientation distribution function (ODF) analysis. Split-Hopkinson Pressure Bar technique was used to generate a high strain rate of > 103 s-1 for preparing the deformed samples. Starting with an almost random texture in a solution treatment condition, the deformed material developed several typical texture components, such as ‘Goss’ texture and ‘Brass’ texture. Compared to the texture components displayed in the state of quasi-static compression deformation, it was found that the high-speed deformation generated much weaker texture components. In combination with the change in microstructures observed by EBSD and TEM technique, the high-energy X-ray diffraction provides a powerful tool for characterizing the strain-rate dependence of grain rotation at each stage of deformation. The deformation heterogeneity evident in our experiment can be explained by a transition of deformation mechanism from the dislocation/twin-dominated mode to shear-band-dominated one with increasing strain rate.