Investigations of orientation and length scale effects on micromechanical responses in polycrystalline zirconium using spherical nanoindentation

Here we investigate the elastic and plastic anisotropy of hexagonal materials as a function of crystal orientation using a high-throughput approach (spherical nanoindentation). Using high purity zirconium as a specific example, we demonstrate the differences in indentation moduli, indentation yield strengths and indentation post-elastic hardening rates over multiple grain orientations. These results are validated against bulk single crystal measurements, as well as data from cubic materials. By varying the indenter size (radius), we are also able to demonstrate indentation size effects in hexagonal materials, including possible signatures of strain hardening due to twin formation in the nanoindentation stress-strain curves.