Study on the indentation behaviors of bicrystals based on crystal plasticity theory

In the past decades, the indentation test has been widely used to determine the mechanical properties of materials. For the micro- or nano-indentation, the indentation response is complex since only one or two grains can be indented by the indenter. In order to investigate the indentation behavior of the grain boundary, the crystal plasticity theory was implemented into finite element model to simulate the indentation behavior of single crystals and bicrystals. The stress distributions on the indented surface and grain boundary were obtained. The results showed that the crystallographic orientations of the neighboring grains had a remarkable influence on the depth-load response and the resolved shear stress distribution of the indented bicrystals. Under the indentation load, stress concentration occurred at the grain boundary, and the stress at the grain boundary increases with the increase of mis-orientation angle of the two neighboring grains.