Thermodynamic and Topological Modeling and Synthesis of Cu-Zr-Ti-Ni–Based Bulk Metallic Glasses by Mechanical Alloying

Abstract

In the present investigation, thermodynamic and topological concepts have been used together to understand the formation of bulk metallic glasses. The article attempts to develop a parameter that combines chemical mixing enthalpy (DH chem ), mismatch entropy normalized by Boltzmann constant (DS r /k B ), and configurational entropy (DS config /R), which can be effectively used to identify the best bulk glass forming compositions in multicomponent systems. The DH chem for multicomponent systems has been calculated by extending the MiedemaÕs macroscopic model, and DS r /k B was obtained from MansooriÕs approach. The iso-DH chem , iso-DS r /k B , and iso-DS config /R contours have been developed. The product of DH chem and DS r /k B in the DS config /R range of 0.9 to 1.0 can be correlated strongly to glass forming ability. This has been demonstrated in the case of the quaternary Cu-Zr-Ti-Ni bulk glass forming system to determine the bulk metallic glass forming compositions. Mechanical alloying is used to prepare the bulk amorphous powder at the compositions predicted by the model in order to validate the model.

On Prediction of Amorphous Phase Forming Compositions in the Iron-Rich Fe-Zr-B Ternary System and Their Synthesis

“…The main advantage of this parameter is its applicability to multicomponent systems, which was missing in earlier predictive models. This parameter was found to correlate well with the GFAs of Zr-Cu-Al, [15] Cu-Zr-Ti, [16] Cu-Zr-Ti-Ni, [17] Zr-Ti-Cu-Ni-Be, [18] and Zr-Ti-Cu-NiAl [19] systems. However, this approach was not extended much to iron-based glass systems, which inherently possess low GFA.…”

Structure, Properties, and Glass Forming Ability of Melt-Spun Fe-Zr-B-Cu Alloys with Different Zr/B Ratios

“…This implies that the glass forming range is large in the case of series 13. In order to evaluate the GFA of Fe-Zr-B-Cu alloy system, a recent approach based on thermodynamic calculations proposed by Bhatt et al [9][10][11] was used. In their approach, thermodynamic and topological models are combined to yield a parameter, P H-S , which is defined as…”

Thermodynamic modeling of Zr-Ti-Cu-Ni-Be bulk metallic glass

“…From the analysis [8,10] for Zr based ternary systems, it was observed that configurational entropy, represented by 'S config /R, ranges from 0.9 to 1.0 for all bulk glass forming compositions and when shown in the form of isocontours, it gives a composition domain for BMG formation in a ternary system as shown in Fig. 1.…”

“…3. A glass forming ability parameter denoted by 'P HS [8,10], which is the product of 'H chem and 'S V /k B was calculated for all the intersections. The intervals between contours for 'H chem and 'S V /k B can be minimized to get more accurate compositions at the intersections.…”

“…The present work is an attempt toward solving this problem. In an earlier work, the present authors have successfully optimized the bulk forming compositions in ternary Zr-Cu-Al [8,9], quaternary Cu-Zr-Ti-Ni [10] and quinary Zr-Ti-Cu-Ni-Al [11] system and now the present work is extended to another quinary Zr-Ti-Cu-Ni-Be system.…”