Locating bulk metallic glasses with high fracture toughness: Chemical effects and composition optimization

He, Qiang; Cheng, Yongqiang; Ma, Evan; Xu, Jie

doi:10.1016/j.actamat.2010.09.025

Cited by 157 publications

(77 citation statements)

References 43 publications

(78 reference statements)

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“…For the considerations of glass-forming ability, Ni and Cu are even sometimes regarded as same 33,34 . Distinctively, we note the mechanical behaviours (especially, the ductility and toughness) of MGs are sensitive to chemical effects 35,36 , in agreement with the notion that mechanical properties and b-relaxations are correlated 21,22 .…”

Section: Resultssupporting

confidence: 52%

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Chemical influence on β-relaxations and the formation of molecule-like metallic glasses

et al. 2013

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Secondary (also known as Johari-Goldstein or b-) relaxations are an intrinsic feature of supercooled liquids and glasses. They are important in many respects but the underlying mechanisms are not well understood. A long-standing puzzle is why some glasses show b-relaxations as pronounced peaks, whereas others as unobvious excess wings. Here we demonstrate that these different behaviours are related to the fluctuations of chemical interactions by using prototypical systems of metallic glasses. A general rule is summarized: pronounced b-relaxations are associated with systems where all the atomic pairs have large similar negative values of enthalpy of mixing, whereas positive or significant fluctuations in enthalpy of mixing suppress b-relaxations. The emerging physical picture is that strong and comparable interactions among all the constituting atoms maintain string-like atomic configurations for the excitations of b-events and can be considered as the formation of molecule-like metallic glasses.

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Section: Resultssupporting

confidence: 52%

“…We first evaluated the mean chemical affinity DH chem for these MGs. As suggested in Takeuchi et al 34 and He et al 35 , the DH chem of a given multicomponents alloy can be estimated using a weighted average approach, ARTICLE to the (Cu 0.5 Zr 0.5 ) 100-x Al x systems. As shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

Chemical influence on β-relaxations and the formation of molecule-like metallic glasses

et al. 2013

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“…26,27 The partial VDOS of these alloys representing Cu vibrational spectra are shown in Figure 6a. Figure 6b depicts the contribution of Cu vibrations to the specific heat of these Zr-based alloys as a function of temperature.…”

Section: Resultsmentioning

confidence: 99%

Softening of phonon spectra in metallic glasses

et al. 2016

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The vibrational spectra of a series of MgZnCa amorphous alloys were computed using density functional theory and implementing the small displacement method. The atomic structures of the alloys were obtained by ab initio molecular dynamics simulations. The vibrational thermodynamic properties were calculated as a function of temperature and, in particular, the specific heat at low temperature was approximated by temperature cubed based on the Debye model. We computed the contribution of Mg vibrations to the specific heat and investigated the softening of Mg phonon spectra, where the maximum allowed vibrational frequency is lowered and highly collective diffusion processes are promoted. The statistical correlation between the reported critical casting thickness of the alloys and softening of Mg phonons was obtained. Similar calculations were performed for two distinctively different amorphous ZrTiCuAl alloys with large and small reported critical casting thickness, respectively. The findings were consistent with those of the MgZnCa alloys. INTRODUCTIONThere has been increasing attention devoted to the effect of vibrational thermodynamics on the formation of different alloy phases and their associated phase transformations due to the improved accessibility of instruments capable of measuring and calculating the phonon frequencies. 1 Various thermodynamic properties such as specific heat and vibrational entropy can be derived through the vibrational density of states (VDOSs). The VDOS obtained by molecular dynamics (MD) simulations has provided useful insight into how phonon spectra are affected by both the size and surface properties of silicon nanoparticles; this is of major significance in the design of nanodevices with better heat transport properties. It was found that, as the Si particles become smaller, the density of vibrational states increases at low frequencies, and modes are transferred from the high-frequency end to the intermediate range and transverse optical modes peak are shifted to higher frequencies. 2 In metallic glasses, vibrational characteristics have also been used for explaining mechanical properties. For example, recent MD simulations of a Cu 64 Zr 36 metallic glass showed that the strongest participation in the modes with lowest vibrational frequency and, hence, weakest spring constants (i.e., soft modes) originate predominantly from meagrely populated polyhedra. These soft spots provide fertile sites for accommodating shear transformations. 3 The softening of long wavelength acoustic phonons in PdSiCu, ZrTiCuNiBe, CeAlNiCu and ZrNbCuNiBe amorphous alloys relative to their crystalline phases have been observed experimentally using ultrasound measurements. [4][5][6] Such observations are consistent with the low-temperature measurements of their specific heat, whereby an increase in temperature causes a steeper increase in specific heat in the amorphous alloys compared with their crystalline counterparts.Specific heat is believed to be a fundamental property of materials and, in particular,...

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“…Более того, следует заметить, что недавно были разработаны сплавы ОМС Zr 61 Ti 2 Cu 25 Al 12 [23] и Pd 79 Ag 3,5 P 6 Si 9,5 Ge 2 [24], об-ладающие рекордно высокой вязкостью разруше-ния -порядка 100 МПа·√ -м. Была также обнаруже-на неупругая однородная деформация в аморфной матрице после снятия упругой [25] и пластической [26,27] деформаций.…”

Section: механические свойства омс при комнатной температуреunclassified

Properties of Bulk Metallic Glasses

Luzgin¹,

Polkin²

2016

Izv.VUZ. Tsvet. Met.

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Металловедение и термическая обработка Izvestiya vuzov. Tsvetnaya metallurgiya • 6 • 2016 71 ВведениеМеталлические стекла, получаемые в виде тон-ких чешуек или лент, известны со второй полови-ны прошлого века [1]. Объемные металлические стекла (ОМС) с минимальным размером порядка 100-102 мм в каждом из 3 пространственных из-мерений [2] изначально были получены в системах Pd-Cu-Si и Pd-Ni-P, но ввиду исключительной дороговизны основного компонента (палладия) долгое время не представляли особого интере-са для ученых и инженеров. Впоследствии ОМС, полученные во многих других системах, включая технологически важные -на основе Fe, Mg, Ti и За последние несколько десятилетий открыто относительно небольшое число революционных материалов в области ме-талловедения и физики металлов, и объемные металлические стекла одни из них. Их прочность и твердость значительно выше, а модуль упругости ниже, чем кристаллических сплавов, что приводит к высокой энергии запасенной упругой деформации. Эти материалы также имеют очень хорошую устойчивость к коррозии. В настоящей работе исследованы свойства объемных металлических стекол, в частности тепловые, механические, магнитные, электрические показатели и коррозионная стойкость, а также приводятся области применения данных сплавов. Louzguine-Luzgin D.V., Pol'kin V.I. Properties of bulk metallic glassesA relatively small number of revolutionary discoveries were made in the field of metallurgy and metal physics in the last few decades, and bulk metallic glasses are one of them. The strength and hardness of bulk metallic glasses are much higher while moduli of elasticity are lower than those of crystalline alloys which results in high stored elastic strain energy. These alloys also have very good corrosion resistance. This article covers various properties of bulk metallic glasses, in particular thermal, mechanical, magnetic, electrical properties and corrosion resistance as well as applications of these alloys.Keywords: bulk metallic glasses, strength, ductility, application.

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Locating bulk metallic glasses with high fracture toughness: Chemical effects and composition optimization

Cited by 157 publications

References 43 publications

Chemical influence on β-relaxations and the formation of molecule-like metallic glasses

Chemical influence on β-relaxations and the formation of molecule-like metallic glasses

Softening of phonon spectra in metallic glasses

Properties of Bulk Metallic Glasses

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