Local mechanical properties in the vicinity of (11¯0)Σ3/[111] symmetric tilt grain boundary in aluminum bicrystal

The local mechanical properties near the (11¯0)Σ3/[111] symmetric tilt grain boundary in a high purity aluminum bicrystal were studied by the nanoindentation technique. The first pop-in load and its width significantly decreased near / at the grain boundary compared to those in the grain interior. The critical stress required to nucleate dislocations at the grain boundary was estimated to be notably lower than that in the grain interior. Moreover, it was found that the slope of the load-penetration curve prior to the first pop-in was smaller near the grain boundary than in the grain interior. This result was discussed in terms of possible micro plasticity effects and decreasing the elastic modulus in the close vicinity of the grain boundary.