Nanoindentation response of Fe-10%Cr bi-crystal structures with σ 5 (0 0 1) and σ 3 (1 1 0) tilt boundaries: An atomistic study

In this research, nanoindentation responses of Fe-10%Cr bi-crystal structures containing σ5{310}(001) and σ3{111}(110) tilt grain boundaries (GBs) have been investigated using atomistic simulation technique. Deformation analyses identify the nucleation of 1/2(111), (001) and 1/6(111) types of dislocations within the material. The {110} slip planes are found to be more active than the {123} and {100} slip planes. Load-displacement response and corresponding changes in contact area have been recorded and used to measure material hardness and reduced modulus. The lengths of the nucleated dislocations are measured and used to estimate dislocation density within the plastic zone beneath the indenter. Dislocation motion has been found to be much easier in model with σ3 boundary and the early interaction of the dislocation with the boundary affects the shape of the load-displacement curve, contact area on the indented surface, and the volume of the plastic zone. The hardness of the material has been found to be affected primarily by the interaction of the dislocation with the boundary, rather than by the dislocation density within the plastic zone. Both the boundaries exhibit maximum resistance to slip transmission even at the maximum indentation depth.