Most of the residual defects on the machining-induced surface are making an angle of 90° with the cutting direction. In this case, most of the surface residual defects 3-deazaneplanocin A move to either [ī0ī] or [ī01] crystal orientations, which also run parallel with the three slip vectors in the FCC crystal. Because of the different cutting directions on the surface, the quality and distribution of residual defects in the damaged layer in the surface are not the same. Once the nanoindentation test begins, this balance is immediately broken,

and the bulk glides are more likely to take place along specific directions. More details about the generated dislocations derived from the residual defects in the subsurface during nanoindentation Apoptosis inhibitor are in the following paragraph. Figure 8 The top view of the machining-induced surface after relaxation in two different cutting directions.

(a) Along [100] and (b) [101] directions. Figure  9 shows the emission of dislocations in the subsurface during nanoindentation beneath the machining-induced surface along the [ī00] and [ī01] crystal orientations, respectively. The machined layer on the surface is invisible for the immobile dislocations make it difficult to identify the newly generated dislocation loops in the surface due to nanoindentation. The movements of partial dislocation loops have often been found in nanoindentation simulations of single-crystal FCC metals in previous studies. They are of great importance in material deformation process because Bay 11-7085 they mediate the plastic deformation. Figure  9 (a1 and a2) shows the cross-sectional view of the specimen beneath the machining-induced surface of 0.28 nm. More dissimilar glide patterns of surface dislocations around the diamond indenter are observed in Figure  9 (a1), which indicates that the extent of the damaged layer under the machined surface along [ī00] is larger than that along [ī01]. The defects around the indenter may lead to the nucleation of dislocations with large hydrostatic pressure under the diamond indenter. Figure  9 (b1 and b2) shows the cross-sectional

view of the specimen beneath the machining-induced surface of 0.51 nm. The directions of the gliding dislocations in the subsurface are implied by the arrows attached to the small circles. The quantity and direction of the dislocations indicate that the subsurface damage is strongly dependent on the nanocutting directions. The number of the dislocations under the machining-induced surface along [ī00] is much larger than that along the [ī01] crystal orientation. As mentioned before, more dislocations beneath the indenter may lead to permanent plastic deformation easily. It is thus well inferred that the hardness of the machining-induced surface along the [ī00] direction is smaller than that along the [ī01] direction. Figure 9 Emission of dislocations.