Indentation Deformation of a Cu_47.5Zr₁₉Hf_28.5A_l5 Bulk-Metallic Glass-Matrix Nanocomposite

In this work, we study the indentation deformation of a Cu_47.5Zr₁₉Hf_28.5A_l5 bulk-metallic glass-matrix composite and characterize the effects of the indentation-loading rate and the holding time at the peak-indentation load. For the same peak-indentation load, increasing the holding time and/or decreasing the indentation-loading rate cause the increase of the indentation depth. There exists the "bulge" of the unloading curve at the onset of the unloading for small indentation-loading rates. The Vickers hardness is a monotonically increasing function of the indentation-loading rate for the same peak-indentation load. For the indentations with the same loading and unloading time of 30 s and without an intermediate stage at the peak-indentation load, the Vickers hardness of the Cu_47.5Zr₁₉Hf_28.5A_l5 bulk-metallic glass-matrix composite decreases with the increase of the indentation load. The strain energy dissipated through plastic deformation during the indentation is a power-law function of the indentation load with a power index of 3/2, and the energy ratio (total energy/plastic energy) linearly increases with the depth ratio (residual indentation depth/maximum indentation depth).