Plastic Deformation and Mechanical Softening of Pd₄₀Cu₃₀Ni₁₀P₂₀ Bulk Metallic Glass During Nanoindentation

Abstract

Nanoindentation tests of Pd 40 Cu 30 Ni 10 P 20 bulk metallic glass were performed over a wide range of indentation rates (from 0.04 up to 6.4 mN s −1 ) under the standard load control mode. New results using the feedback displacement control mode are also presented. The dependence of the pop-in formation on the loading rate is investigated. Variations in hardness and reduced elastic modulus as a function of the indentation rate are observed. A softening effect occurs when increasing the loading rate. This is explained by the differences in plastic deformation achieved at different indentation rates. The displacement control mode was used to avoid the shear localization of the free volume, leading to the almost complete absence of pop-ins along the loading curve. The obtained results suggest that plastic flow in bulk metallic glasses is governed by the rate of creation of free volume, which depends on the strain rate and its localization into shear bands.

Anelastic deformation of a Pd40Cu30Ni10P20 bulk metallic glass during nanoindentation

“…This is contrary to what was reported in Ref. 16, where the authors used an exceedingly short ͑i.e., 2 s͒ holding segment. As a consequence, the hardness and the reduced elastic modulus are independent of the loading rate, as shown in Table I.…”

“…11 Recently, several authors have studied the mechanisms of plastic deformation in BMGs by means of nanoindentation. [12][13][14][15][16][17] In nanoindentation of BMGs, plastic deformation is manifested as pop-in events on the load-displacement curves during loading. 12 These serrations, which are more pronounced for low loading rates, have been related to the formation and propagation of shear bands.…”

“…12 These serrations, which are more pronounced for low loading rates, have been related to the formation and propagation of shear bands. [14][15][16][17] Although plastic deformation during nanoindentation has been studied to some extent in BMGs, time-dependent deformation effects have generally been overlooked. Apart from its fundamental interest, the creep of submicrometer contacts is also of clear practical significance.…”

Tailoring the physical properties of electrodeposited CoNiReP alloys with large Re content by direct, pulse, and reverse pulse current techniques

“…24 Osaka's group contributed significantly in this field by producing 25 electroless-deposited continuous films and patterned nanostruc- 26 tures of CoNiReP [1][2][3][4][5]. These films were mostly Ni-rich, and only 27 under specific conditions, did the Co content surpass that of Ni.…”

Influence of the shot-peening intensity on the structure and near-surface mechanical properties of Ti40Zr10Cu38Pd12 bulk metallic glass

“…3,[16][17][18] Nanoindentation data (Fig. 3) show the profile of H, E r , U pl /U tot , and r y /E as a function of distance from the surface for S 1 and S 2 samples.…”