Chemical bonding effects on the brittle-to-ductile transition in metallic glasses

Moitzi, Franco; Şopu, Daniel; Holec, David; Perera, Delwin; Mousseau, Normand; Eckert, J.

doi:10.1016/j.actamat.2020.02.002

Cited by 36 publications

(7 citation statements)

References 54 publications

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“…The influence of covalent bonding seems to be the key parameter for the frustration of icosahedral structures 46,47 . Thus, the observed increase in the variety of structural motifs as well as their population in the glassy state for Pd 40 Ni 40 P 20 enables the possibility of forming an enhanced heterogeneity 41 over extended medium range affecting its plasticity, similar to observations in PdSi 46,48 and AlSm 49 . The structural heterogeneity may also be classified as a sort of polyamorphism; not, however, in the strict sense of a first order transformation between two phases but rather as distinguishable structural MRO networks.…”

Section: Modelssupporting

confidence: 65%

What renders bulk metallic glass ductile/brittle? -- new insight from the medium-range order

Davani,

Hilke,

Rösner

et al. 2020

Preprint

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Understanding ductility or brittleness of monolithic bulk metallic glasses (BMGs) requires detailed knowledge of the amorphous structure. The medium range order (MRO) of ductile Pd 40 Ni 40 P 20 and brittle Zr 52.5 Cu 17.9 Ni 14.6 Al 10 Ti 5 (Vit105) was characterized prior to and after notched 3-point bending tests using variable-resolution fluctuation electron microscopy. Here we show the presence of a second larger MRO correlation length in the ductile material which is not present in the brittle material. A comparison with literature suggests that the larger correlation length accounts for larger shear transformation zones (STZs) which increase the heterogeneity. This enables an easier shear band formation and thus explains the difference in deformability.

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Section: Modelssupporting

confidence: 65%

What renders bulk metallic glass ductile/brittle? -- new insight from the medium-range order

Davani,

Hilke,

Rösner

et al. 2020

Preprint

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show abstract

“…Recent molecular dynamics (MD) simulations showed that at the glass transition the motif distribution in metal-metal MGs changed towards an increase in "icosahedral-like" order in the supercooled liquid 63 . On the other hand, for metalmetalloid MGs the influence of covalent bonding seems to be the key parameter leading to a frustration of icosahedral structures 7,58,[64][65][66] . This different population of motifs 64 may influence the thermal stability of certain MRO types in the BMG, even above T g .…”

Section: A Calorimetric Observations By Dsc and Ppmsmentioning

confidence: 99%

Impact of Severe Deformation by HPT at Room Temperature on the Relaxation of the Glassy and the Supercooled Liquid States of PdNiP

et al. 2019

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The impact of severe plastic deformation by high-pressure torsion on the relaxation of the glassy and supercooled liquid states of Pd 40 Ni 40 P 20 was investigated using a combination of differential scanning calorimetry, low-temperature heat capacity and fluctuation electron microscopy. The changes in the calorimetric signals due to deformation and subsequent heat treatments were analyzed and a correlation between deformation (rejuvenation) and annealing (relaxation) was found in relation to medium-range order (MRO). Moreover, a coupling between the occurrence of an exothermic peak in the supercooled liquid state and specific changes in the MRO types were identified. These findings are comprehended in a potential energy landscape scheme offering a new approach for MRO engineering of glasses.

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“…The results reveal that the Poisson's ratios of the spinel phases were between v = 0.25 and 0.33, indicating ionic and metallic bonding in all atoms of the spinel compound. The Poisson's ratio is an index that describes the directionality of chemical bond; it is v = 0.1, for covalent bonds, v = 0.25 for ionic bonds, and v = 0.33 for metallic bonds [42]:…”

Section: Resultsmentioning

confidence: 99%

Corrosion Protection Oxide Scale Formed on Surface of Fe-Ni-M (M = Al, Cr, Cu) Inert Anode for Molten Salt Electrolysis

et al. 2022

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An oxide scale formed on the surface of metal anodes is crucial for determining the overall quality of molten salt electrolysis (MSE), particularly for the durability of the anode materials. However, the material properties of oxide scales are yet to be revealed, particularly in ternary spinel oxide phases. Therefore, we investigate the mechanical and thermal properties of spinel oxides via first-principles calculations. The oxides are calculated using the models of normal (cubic) and inverse (orthorhombic) spinel compounds. The d-orbital exchange correlation potential of transition metal oxides is addressed using the generalized gradient approximation plus Hubbard U. The lattice constant, formation energy, cohesive energy, elastic modulus, Poisson’s ratio, universal anisotropy index, hardness, minimal thermal conductivity, and thermal expansion coefficient are calculated. Based on the calculated mechanical and thermal properties of the spinel compound, the Fe–Ni–Al inert anode is expected to be the most suitable oxide scale for MSE applications among the materials investigated in our study.

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Chemical bonding effects on the brittle-to-ductile transition in metallic glasses

Cited by 36 publications

References 54 publications

What renders bulk metallic glass ductile/brittle? -- new insight from the medium-range order

What renders bulk metallic glass ductile/brittle? -- new insight from the medium-range order

Impact of Severe Deformation by HPT at Room Temperature on the Relaxation of the Glassy and the Supercooled Liquid States of PdNiP

Corrosion Protection Oxide Scale Formed on Surface of Fe-Ni-M (M = Al, Cr, Cu) Inert Anode for Molten Salt Electrolysis

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