The role of Ga addition on the thermodynamics, kinetics, and tarnishing properties of the Au-Ag-Pd-Cu-Si bulk metallic glass forming system

Neuber, Nico; Gross, Oliver; Eisenbart, Miriam; Heiss, Alexander; Klotz, Ulrich; Best, James P.; Polyakov, Mikhail N.; Michler, Johann; Busch, Ralf; Gallino, Isabella

doi:10.1016/j.actamat.2018.11.052

Cited by 25 publications

(11 citation statements)

References 38 publications

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“…Although the two selected compositions would appear as identical in topological structural models 16 , they present different structural motifs on the MRO and SRO length scales 18 , which influence their relaxation dynamics. The kinetic fragility -described by the temperature evolution of the microscopic relaxation time -is insensitive to the composition and is similar for both alloys, in agreement with macroscopic studies 49,71 . In contrast, the two liquids have different structural fragilities which mirror the different temperature dependence of the β(Q FSDP ,T) parameter describing the heterogeneous nature of the dynamics.…”

Section: Discussionsupporting

confidence: 83%

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Disentangling structural and kinetic components of the α-relaxation in supercooled metallic liquids

et al. 2022

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The particle motion associated to the α-relaxation in supercooled liquids is still challenging scientists due to its difficulty to be probed experimentally. By combining synchrotron techniques, we report the existence of microscopic structure-dynamics relationships in Pt42.5Cu27Ni9.5P21 and Pd42.5Cu27Ni9.5P21 liquids which allows us to disentangle structural and kinetic contributions to the α-process. While the two alloys show similar kinetic fragilities, their structural fragilities differ and correlate with the temperature dependence of the stretching parameter describing the decay of the density fluctuations. This implies that the evolution of dynamical heterogeneities in supercooled alloys is determined by the rigidity of the melt structure. We find also that the atomic motion not only reflects the topological order but also the chemical short-range order, which can lead to a surprising slowdown of the α-process at the mesoscopic length scale. These results will contribute to the comprehension of the glass transition, which is still missing.

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Section: Discussionsupporting

confidence: 83%

“…During the isothermal measurements the same heating rate of 0.333 Ks −1 was applied to reach the desired isothermal plateau temperature. A more detailed description of the technique and calculations to obtain the viscosity from the deflection rate can be found in literature 19,71 .…”

Section: Methodsmentioning

confidence: 99%

Disentangling structural and kinetic components of the α-relaxation in supercooled metallic liquids

et al. 2022

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“…Hence, the fragility of a glass forming liquid is a crucial factor to understand and evaluate its GFA and is therefore of interest for scienti c research, but also for technological applications. Fragility can be determined experimentally by using thermo-mechanical analysis [5,9,22], dynamic-mechanical analysis [23,24], or calorimetric methods. One calorimetric approach is the so called T g -shift method that measures the dependence of the thermal glass transition on the applied rate of temperature change [13,22,25,26].…”

Section: Introductionmentioning

confidence: 99%

Determining the fragility of bulk metallic glass forming liquids via modulated DSC

Frey

Neuber

Gross

et al. 2020

J. Phys.: Condens. Matter

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Temperature modulated DSC is used to study the fragility of three different bulk metallic glass forming liquids. Through applying various modulation frequencies, the dynamic glass transition shifts in temperature, allowing to determine the temperature dependence of the average relaxation time for each system. The resulting fragilities are compared with fragility investigations in literature obtained using thermo-mechanical analysis and the heating rate dependence of the calorimetric glass transition. Different methods to compare the data are evaluated and discussed.

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“…This points towards a two-step isothermal crystallization process with a faster primary and a slower secondary crystallization (see SI-gure II). The appearance of several steps in the crystallization process is expected since the crystallization in an up-scan with a conventional DSC is also appearing as a four-step process [7]. More surprising is an unexpected shift of the crystallization times between 523 K (250 • C) and 473 K (200 • C).…”

Section: Resultsmentioning

confidence: 92%

“…Regarding the GFA of the AuGa alloy, a bene cial kinetic slow-down through these adjustment was observed and the reduction in GFA was traced back to thermodynamic origins [7]. The reduction in glass-forming ability of the Gacontaining alloy has somehow to translate to the TTT-diagram.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast scanning calorimetry of newly developed Au-Ga bulk metallic glasses

Neuber

Frey

Gross

et al. 2020

J. Phys.: Condens. Matter

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The isothermal crystallization times and critical cooling rates of the liquid phase are determined for the two bulk metallic glass forming alloys Au 49 Ag 5.5 Pd 2.3 Cu 26.9 Si 16.3 and Au 51.6 Ag 5.8 Pd 2.4 Cu 20.2 Ga 6.7 Si 13.3 by using fast differential scanning calorimetry, covering the whole timescale of the crystallization event of the metallic melt. In the case of Au 49 Ag 5.5 Pd 2.3 Cu 26.9 Si 16.3 , a typical crystallization nose was observed, whereas for the Au 51.6 Ag 5.8 Pd 2.4 Cu 20.2 Ga 6.7 Si 13.3 , a more complex crystallization behavior with two distinct crystallization noses was found. Even for the complex crystallization behavior of the Au 51.6 Ag 5.8 Pd 2.4 Cu 20.2 Ga 6.7 Si 13.3 alloy it is shown that the minimal isothermal nose time τ * x does allow for a quanti cation of the macroscopic critical thickness. It is discussed in contrast to the critical cooling rate, which is found to allow less exact calculations of the critical thickness and thus does not correlate well with the critical cooling rate from macroscopic experiments. Additionally the crystallization data of Au 49 Ag 5.5 Pd 2.3 Cu 26.9 Si 16.3 was modeled using classical nucleation theory with the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation, enabling a determination of the interfacial energy.

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The role of Ga addition on the thermodynamics, kinetics, and tarnishing properties of the Au-Ag-Pd-Cu-Si bulk metallic glass forming system

Cited by 25 publications

References 38 publications

Disentangling structural and kinetic components of the α-relaxation in supercooled metallic liquids

Disentangling structural and kinetic components of the α-relaxation in supercooled metallic liquids

Determining the fragility of bulk metallic glass forming liquids via modulated DSC

Ultrafast scanning calorimetry of newly developed Au-Ga bulk metallic glasses

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