Influence of crystal orientation on hardness and nanoindentation deformation in ion-irradiated stainless steels

The influence of crystal orientation on hardness and the range of plastic deformation caused by nanoindentation was investigated in a solution annealed type 316 stainless steel irradiated with Fe2+ ions. The hardness was a function of grain orientation and was correlated with the Taylor factor averaged over three normal directions of the contact surface of the Berkovich indenter. The transmission electron microscope observations of the deformation microstructure under the indentations showed that the range of plastic deformation reached up to 10 times the indent depth for unirradiated material and depended on the orientation relation between the contact surface of the indenter and the slip directions. The range of plastic deformation decreased as the damage structure developed in ion irradiation.