Hardness variation across a Zr₅₇Ti₅Cu₂₀Ni₈Al₁₀ bulk metallic glass

Excerpt

Indentation test has recently been used to examine mechanical properties of bulk metallic glasses (BMGs). Donovan [1] observed the radial incipient cracks and the curving Hartmann lines in the deformation zone for the indentation of a Pd₄₀Ni₄₀P₂₀ BMG. Jana et al. [2] revealed several sets of slip-steps from shear bands for the Vickers indentation of Pd_42.1Ni_39.77P_18.13 and Zr_56.69Cu_26.96Al_10.95Ni_5.4 BMGs. Ramamurty et al. [3] used the bonded interface technique to examine the pattern of shear bands underneath the Vickers indentation in a Pd₄₂Ni₄₀P₁₈ BMG. Jana et al. [4] evaluated the subsurface deformation topology in the Vickers indentation of a Zr₅₇Cu₂₇Al₁₁Ni₅ BMG. Zhang et al. [5] investigated the evolution of shear bands in a Vitreloy 106 beneath a Vickers indentation. Yang et al. [6] observed surface wrinkling in the nanoindentation of a Zr-based BMG. Wang et al. [7] revealed the occurrence of serrated flow in the indentation of a Zr-based BMG. Golovin et al. [8] observed the occurrence of the pop-in in the loading phase for the indentation of a Pd-based BMG and noted that the dependence of the strain-serration on the indentation depth. Schuh and Nieh [9, 10] reported the serrated flow and suggested that the indentation-induced plastic flow could be a strong function of the indentation rate. Recently, Greer et al. [11] suggested that the absence of the serrated flow and the pop-in phenomenon at small indentation depth may be due to the lack of the resolution in instrument. However, there is little work on the dependence of the indentation deformation on the indentation position, related to the flow defect concentration from the solidification process in the preparation of bulk metallic glasses. …