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Taylor’s series expansion is employed for the computation of thermodynamical parameters of a selected sample of bulk metallic glass (BMG). A comparative study is also prepared between the present study result and the experimental results as well as the results obtained on the basis of various theoretical models. An attempt is also made to correlate the glass forming ability with the reduced glass transition temperature.

Using a model that describes the viscosity of liquids in terms of physical parameters, researchers found a correlation between fragility and interparticle repulsion in glass-forming liquids.

Researchers explore why viscous liquid dynamics at low temperatures seem to follow a model meant for disordered solids.Researchers explore why viscous liquid dynamics at low temperatures seem to fo...

The glass forming ability (GFA) of Cu–Zr alloys has been still ambiguous, due to incomplete or lacking thermophysical properties of Cu–Zr liquids in supercooled and stable states, although tremendous effort has been devoted. We provide here the comprehensive thermophysical properties of Cu–Zr liquids, such as undercoolability, density, viscosity, fusion enthalpy, temperature–time-transformation (TTT) diagram, and crystal–liquid interfacial free energy. Three compositions, Cu64Zr36, Cu56Zr44, and Cu50Zr50, show distinctive anomalies in undercoolability, nose time in TTT, and crystal–liquid interfacial free energy, but not in density and viscosity in supercooled and stable liquid states. The anomalies reflect that the GFA is dominantly governed by thermodynamics rather than kinetics in these bulk metallic glasses (BMGs). In addition, we find that positions of nose temperatures in the TTT curves are below 1/2 (Tg + Tl), which implies unequal contribution of thermodynamics and kinetics. We discuss that empirical GFA parameters cannot explain the glass formation of Cu–Zr alloys due to the unequal contribution, and the Turnbull GFA criterion (Trg = Tg/Tl) is valid for the equal contribution of the two effects. The present experimental findings shed light on the ongoing debate about the GFA criterion of Cu–Zr BMGs.

In the present work, the Non-Equilibrium Self-Consistent Generalized Langevin Equation (NESCGLE) theory is used to predict the final state of glass-forming liquids subjected to different cooling processes. We show that the NESCGLE theory correctly describes two essential features of the glass transition. Such features are the structural recovery and the dependence of the final state with the cooling rate. We demonstrate that below a particular temperature Tc, the system is unable to equilibrate, independently of the cooling rate. We show that the equilibrium state is only reached for the quasistatic process. Additionally, we show how, from the NESCGLE theory, it is possible to deduce a relaxation model of structural recovery, for which we obtain molecular expressions of the parameters.

Glass-formation is a ubiquitous phenomenon that is often observed in a broad class of materials ranging from biological matter to commonly encountered synthetic polymer, as well as metallic and inorganic glass-forming (GF) materials. Despite the many regularities in the dynamical properties of GF materials, the structural origin of the universal dynamical properties of these materials has not yet been identified. Recent simulations of coarse-grained polymeric GF liquids have indicated the coexistence of clusters of mobile and immobile particles that appear to be directly linked, respectively, to the rate of molecular diffusion and structural relaxation. The present work examines the extent to which these distinct types of "dynamic heterogeneity" (DH) arise in metallic GF liquids (Cu-Zr, Ni-Nb, and Pd-Si alloys) having a vastly different molecular structure and chemistry. We first identified mobile and immobile particles and their transient clusters and found the DH in the metallic alloys to be remarkably similar in form to polymeric GF liquids, confirming the "universality" of the DH phenomenon. Furthermore, the lifetime of the mobile particle clusters was found to be directly related to the rate of diffusion in these materials, while the lifetime of immobile particles was found to be proportional to the structural relaxation time, providing some insight into the origin of decoupling in GF liquids. An examination of particles having a locally preferred atomic packing, and clusters of such particles, suggests that there is no one-to-one relation between these populations of particles so that an understanding of the origin of DH in terms of static fluid structure remains elusive.

This paper presents a set of general strategies for the analysis of structure in amorphous materials and a general approach to assessing the utility of a selected structural description. Measures of structural diversity and utility are defined and applied to two model glass forming binary atomic alloys. In addition, a new measure of incipient crystal-like organization is introduced, suitable for cases where the stable crystal is a compound structure.

Using extrinsic probes to study a host system relies on the probes’ ability to accurately report the host properties under study. Probes have long been used to characterize dynamic heterogeneity, the phenomenon in which a liquid near its glass transition exhibits distinct dynamics as a function of time and position, with molecules within nanometers of each other exhibiting dynamics that may vary by orders of magnitude. The spatial and temporal characteristics of dynamic heterogeneity demand the selection of probes using stringent criteria on their size and dynamics. In this report, we study the dynamic heterogeneity of the prototypical molecular glass former o-terphenyl by investigating single molecule rotation of two perylene dicarboximide probe molecules that differ in size and comparing this to results obtained previously with the probe BODIPY268. It is found that a probe’s ability to accurately report dynamic heterogeneity in o-terphenyl depends on whether the reported distribution of dynamics overlaps with the intrinsic dynamics of the host, which is naturally related to the width of the intrinsic dynamics and the magnitude of dynamical shift in probe dynamics relative to the host. We show that a probe that rotates ≈15 times more slowly than the intrinsic dynamics of the host o-terphenyl senses the slowest ≈5% of the full dynamic heterogeneity whereas one that rotates ≈65 times more slowly than the host fails to report dynamic heterogeneity of the host.

We have investigated the enthalpic and dielectric relaxations of four groups of quinoline analogs having similar structural properties (i.e., rigidity, stiffness, and bulkiness) but a different steric character and the nature of intermolecular interactions and flexibility. The dielectric fragility index (md) and the enthalpic one (mH), determined by the Tool–Narayanaswamy–Moynihan–Hodge formalism, are comparable. Generally, for the four sets of molecules of similar structures, both the interactions and flexibility are found to be critical in making the large span of fragility (i.e., from 59 to 131) and glass forming ability. By contrast, individual impacts of the interaction and flexibility can only explain fragility partly among each group of isomers. We found that the molecules with high fragility are of relatively low liquid density, reflecting the joint impact of the interactions and flexibility. An interesting result is observed among the isomers that the molecules which are fragile have enhanced glass forming ability. The results are unveiling the joint impacts of molecular structure (flexibility) and intermolecular interaction on the molecular dynamics.

We reformulate the interpretation of the mean-field glass transition scenario for finite dimensional systems, proposed by Wolynes and collaborators. This allows us to establish clearly a temperature dependent length xi* above which the mean-field glass transition picture has to be modified. We argue in favor of the mosaic state introduced by Wolynes and collaborators, which leads to the Adam-Gibbs relation between the viscosity and configurational entropy of glass forming liquids. Our argument is a mixture of thermodynamics and kinetics, partly inspired by the Random Energy Model: small clusters of particles are thermodynamically frozen in low energy states, whereas large clusters are kinetically frozen by large activation energies. The relevant relaxation time is that of the smallest `liquid' clusters. Some physical consequences are discussed.

The excess Gibbs free-energy difference, ΔG1−s, between the undercooled liquid and the crystalline solid for La–Al–Ni–Cu–(Co) alloys was calculated by using directly measured heat capacity data. The glass-forming tendency of these liquids correlated well with the computed Gibbs free-energy difference. The small value of Gibbs free energy of the undercooled liquid with respect to the crystalline solid is a contributing factor to the high glass-forming ability in this system. The kinetics of bulk La–Al–Ni–Cu–(Co) glass-forming liquids were also investigated using differential scanning calorimetry. The fragility plot of the viscosities indicate that these bulk metallic glass formers are strong liquids. The glass-forming ability of these alloys is also explained in the light of this fragility concept.

We have carried out NPT molecular dynamics simulations of isolated ellipsoids in a glass forming binary mixture to gain insight into the nature of orientational relaxation (OR) in a viscous liquid. At high pressures when the liquid is highly viscous, the OR is found to occur mainly via correlated hopping, sometimes involving participation of several neighboring atoms, placed in a ring like tunnel. In the glassy state, hopping is found to be accompanied by larger fluctuations in the total energy and the volume of the system. Both orientational and translational hopping are found to be gated, restricted primarily by the entropic bottlenecks, with the orientational motion becoming increasingly slower than the translation as the pressure is increased. Orientational relaxation is found to occur with a wide distribution of decay times.

Contrary to the established ideas that glasses and glass-forming liquids are homogeneous and isotropic, appreciable structural and compositional heterogeneities are observed in these states. The nature of the heterogeneities in glasses and glass-forming liquids is considered, and the influence of these heterogeneities on the properties of magnetic glasses is examined. Heterophase fluctuations (HPFs), which are nonperturbative disturbances, can play an important role in the thermodynamics of glass-forming liquids, and under certain conditions the liquid has a critical point. The heterogeneities generated in the liquid and glassy states by the HPFs are considered, and the Ginzburg–Landau equations for the HPFs are derived. The order parameter chosen is the fraction of noncrystalline solid-state clusters in the liquid. The correlation length of the order parameter is the characteristic mesoscopic scale of the heterogeneities. The mesoscopic compositional and topological disorder of a glass “spills over” into...

In this article, we derive a rate model, the “cooperative free volume” (CFV) model, to explain relaxation dynamics in terms of a system’s free volume, Vfree, and its temperature, T, over widely varied pressure dependent conditions. In the CFV model, the rate a molecule moves a distance on the order of its own size is dependent on the cooperation of surrounding molecules to open up enough free space. To test CFV, we have generated extensive T,V dependent simulation data for structural relaxation times, τ, on a Kob and Andersen type Lennard-Jones (KA-LJ) fluid. The Vfree = V − Vhc values are obtained by estimating the limiting hard core volume, Vhc, through analysis of the KA-LJ PVT data. We provide the first simulation evidence that shows ln τ to be linearly proportional to 1/Vfree on isotherms, with T-dependent slopes, thus confirming our recent analysis of experimental systems. The linear relationship exhibited by the simulation data is further shown to occur at temperatures both above and below the tran...

We examine the thermodynamics of supercooled liquids focusing on the immediate vicinity of an onset temperature, TA, where system dynamics just begin to experience caging effects. Simulation data from a polymer model and from small molecule mixtures show, in agreement with experiment, that the configurational entropy becomes strongly temperature dependent below TA. Since the diffusion coefficient follows the Adam-Gibbs relationship, our results clearly establish a thermodynamic connection to the localized dynamics of glass-forming liquids.

This investigation focuses on liquid fragility (m) and its correlation with glass-forming ability (GFA) of Ce-Ga-Cu, Ce-Al-Cu-Ni and newly developed Ce-Ga-Cu-Ni bulk metallic glass (BMG) systems. The present Ce-based BMGs belong to the extremely strong glass-forming system, whose fragility m values lie in a strong liquid range of 18–33. The quantitative correlation between m and GFA in the present Ce-based BMGs cannot be described well by previous criteria proposed by Senkov [Phys. Rev. B 76, 104202 (2007)], Wang [Appl. Phys. Lett. 100, 261913 (2012)], and Johnson [Nat. Commun. 7, 10313 (2016)]. By considering both the stability of the liquid phase and the stability of the competing crystalline phases, it is found that the stability of the competing crystalline phases plays a dominant role in the determination of GFA of strong Ce-based BMGs. And, the influence of reduced glass transition temperature (Trg) on GFA would be submerged by that of fragility m when m is below ∼30. The results help in further und...

We describe a method to determine whether a material has isomorphs in its thermodynamic phase diagram. Isomorphs are state points for which various properties are invariant in reduced units. Such materials are commonly identified from strong correlation between thermal fluctuations of the potential energy, U, and the virial W, but this identification is not generally applicable to real materials. We show from molecular dynamic simulations of atomic, molecular, and polymeric materials that systems with strong U-W correlation cannot be pressure densified; that is, the density obtained on cooling to the glassy state and releasing the pressure is independent of the pressure applied during cooling., 9 pages, 3 figures

Wide band dielectric spectroscopy has been used to study the bulk dynamics of the simple supercooled liquid m-toluidine. Following the temperature and frequency dependence of the dielectric response we find a stretched relaxation process, the stretching parameter of which is temperature dependent. The observed decoupling between rotational and translational diffusion parameters at low temperatures may be the result of heterogeneous dynamics.

The glass transition relaxation in m-toluidine was studied by thermally stimulated depolarization currents (TSDC). The departure from the zero entropy prediction, also called compensation behavior, was analyzed and the fragility index of the glass-former m-toluidine was calculated from the TSDC data according to a recently proposed procedure. The obtained result was compared with literature values. A particular attention was focused on the physical aging process of the nonequilibrium glass, which was followed easily because of its slow evolution. The influence of the aging temperature on the aging rate was analyzed. The significance of the so-called compensation point was discussed on the basis of the results obtained in this study of structural aging.

By using molecular dynamics simulation with an n-body Ni–Mo potential, the relative stability of the Ni- and Mo-based solid solutions versus their amorphous counterparts is studied as a function of solute concentrations at 300 K. It is observed that the supersaturated terminal solid solutions have the maximum or critical solute concentrations of 21 at. % of Mo in Ni and 25 at. % of Ni in Mo, respectively, beyond which the solid solutions transform into an amorphous phase. As such, the glass-forming range of the Ni–Mo system is derived to be 21–75 at. % of Mo. The computed critical solute concentrations are compared with those predicted by the generalized Lindemann melting criterion as well as with those revealed by ion-beam mixing/solid-state interdiffusion reaction experiments of Ni–Mo multilayered films.

Small angle x-ray scattering (SAXS) and Rayleigh–Mandelstam–Brillouin (RMB) light scattering as well as ultrasonic sound velocities have been studied in glasses of the system PbO–SiO2 which has an unusually wide range of glass forming ability. The results of scattering are compared with calculations based on the concept of frozen-in equilibrium thermal fluctuations as the origin of static microinhomogeneities (MIH) in glasses. MIH of compositions seem to be the main source of scattering, and the calculations are found to be in qualitative agreement with both SAXS and RMB measurements. Glasses with PbO content above 40 mol.% are more homogeneous than ideal solutions of PbO and SiO2 whereas MIH in glasses with smaller PbO content are comparable with those expected for ideal solutions of PbO and SiO2. In the latter range SAXS measurements indicate the existence of medium-range order with correlation length of 5–7 A.

A knee-shaped feature observed earlier in light scattering spectra of Ca0.4K0.3(NO3)1.4 (CKN) below Tc is used as a strong argument in favor of mode-coupling theory of the glass transition (MCT). Our careful measurements reveal no “knee” in the spectra of two glass forming liquids, CKN and ortho-terphenyl. Instead of the knee the spectra show nontrivial broadening and an increase of the intensity with a temperature increase. Both variations are confirmed by neutron scattering measurements on CKN and are neither expected in the asymptotic MCT predictions nor in any other model.

α and β relaxation time of glass forming solution LiCl–6H2O have been measured in three states; liquid, supercooled liquid, and glass. The β process presents an original behavior which is analyzed. By using the Adam Gibbs and the Coupling Rearranging Region theory, we try to describe the α process. The predictive model of Perez based on these two theories give excellent results and a coherent interpretation of the observed phenomenon.

Molten Pd83.5−xCuxSi16.5 alloys, where 0⩽x⩽27, were allowed to crystallize at temperatures not too far removed from their liquidus T1. The crystalline phases in the as-crystallized specimens were then identified. An attempt was made to correlate the glass forming ability of Pd83.5−xCuxSi16.5 alloys with the crystalline phases formed upon their solidification from the molten state.

Some secondary or β relaxations in glass-forming materials involve molecular motions that bear strong resemblance to the primitive α relaxations of the coupling model, although the two are not identical. For these β relaxations, at the glass transition temperature Tg the relaxation time τβ(Tg) is expected to be shorter than but not too different in order of magnitude from τ0(Tg), the primitive α-relaxation time at Tg. The latter can be calculated by the coupling model from the relaxation time τα(Tg), the exponent (1−n) of the Kohlrausch–Williams–Watts (KWW) correlation function exp[−(t/τα)1−n], and the experimental crossover time, tc≈2 ps, of the α relaxation. From experimental data of β and α relaxations in a variety of glass-forming materials, it is found that τβ(Tg) and τ0(Tg) are close to each other in order of magnitude as anticipated. The results indicate these β relaxations indeed bear some close relation to the corresponding primitive α relaxation, although they are not the same process. Since the...

We compare dielectric relaxation τ(T) data of several low molecular weight glass-forming liquids with the predictions of the Adam–Gibbs theory using experimental data for the configurational entropy Sc(T). Combination of Adam–Gibbs and Vogel–Fulcher equations yields an expression for Sc(T) which can be compared with experimental data. Good agreement is found for a range of temperatures near Tg

Higher order correlation functions as observed in four-dimensional NMR experiments on glass-forming liquids are interpreted in terms of a simple model for molecular reorientations. Its key assumption is an intrinsic link between the rotational and structural relaxation of the liquid. It is shown that the introduction of an additional time scale as proposed previously is not necessary. Furthermore, the model naturally accounts for a number of features associated with rotational motions in supercooled liquids. Applications of the model to other aspects of the α relaxation in supercooled liquids are discussed.

Slow structural relaxations can complicate the interpretation of thermodynamic measurements on glass-forming liquids. Here we demonstrate using model calculations that structural recovery can lead to an apparent frequency-dependent heat capacity in ac calorimetry experiments. The model is shown to describe the complex heat capacity data reported in the literature for glycerol and poly(vinyl acetate). Importantly, the model does not invoke a complex heat capacity; rather, only static heat capacities are used. The analysis further suggests that ac calorimetry should provide a powerful way of testing models of structural recovery.

In this paper, we introduce a method of analysis of the dielectric relaxation data, which results to be very suitable for studying the coalescence of the α and β processes in the time domain. We show that, at least in the case of the glass‐forming liquid BCDE (bis‐phenol‐C‐dimethylether), the coalescence process can be well described by assuming that both, the α and β processes, behave as statistically independent processes. This simple assumption allows to describe the coalescence range of the two processes by extrapolating the low temperature behavior (where both processes are well separated), contrary to more classical approaches in which one needs to introduce a temperature at which the mechanism of the β process changes.

We present a comparative study of the glass forming ability of binary systems with varying composition, where the systems have similar global crystalline structure (CsCl+fcc). Biased Monte Carlo simulations using umbrella sampling technique shows that the free energy cost to create a CsCl nucleus increases as the composition of the smaller particles are decreased. We find that the systems with comparatively lower free energy cost to form CsCl nucleus exhibit more pronounced pre-crystalline demixing near the liquid/crystal interface. The structural frustration between the CsCl and fcc crystal demands this demixing. We show that closer to the equimolar mixture the entropic penalty for demixing is lower and a glass forming system may crystallize spontaneously when seeded with a nucleus. This entropic penalty as a function of composition shows a non-monotonic behavior with a maximum at a composition similar to the well known Kob-Anderson (KA) model. Although the KA model shows the maximum entropic penalty and thus maximum frustration against CsCl formation, it also shows a strong tendency towards crystallization into fcc lattice of the larger "A" particles which can be explained from the study of the energetics. Thus for systems closer to the equimolar mixture although it is the requirement of demixing which provides their stability against crystallization, for KA model it is not demixing but slow dynamics and structural frustration caused by the locally favored structure around the smaller "B" particles which make it a good glass former. Although the glass forming binary systems studied here are quite similar, differing only in composition, we find that their glass forming ability cannot be attributed to a single phenomena., 11pages,15 figures

The point-to-set correlation function has proved to be a very valuable tool to probe structural correlations in disordered systems, but more than that, its detailed behavior has been used to try to draw information on the mechanisms leading to glassy behavior in supercooled liquids. For this reason it is of primary importance to discern which of those details are peculiar to glassy systems, and which are general features of confinement. Thus the concerns raised in Ref. 1 definitely need to meet an answer. The Comment proposes an alternative analysis of the numerical data presented in Ref. 2, according to which the behaviour of the point-to-set correlation function can be interpreted as a linear superposition of boundary effects, rather than the effect of non-trivial thermodynamics. We believe this alternative explanation is not compelling., Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas

We investigated the influence of particle size on the microstructure and magnetocaloric effect of Fe-based alloy powders (11 μm to 100 μm in diameter). The degree of structure order varies with the powder size. The 11 μm to 18 μm powders show the largest peak magnetic entropy change (MEC). Increasing the degree of structure order tends to decrease the maximum MEC. Nevertheless, enhancement of refrigerant capacity and MEC (above 70 K) is achieved when the crystalline phase content is ∼50% (above 75 μm) in the 75 μm to 100 μm powders. Exponent n of the field dependence of MEC increases with the decrease in powder size above 22.5 K. The size dependence of the structure and properties is associated with the fact that a larger particle has a slower cooling rate and takes a longer time to form medium-to-long range ordered structures.

Nonexponential relaxation in glass forming liquids has been attributed by Robertson and Donth to inhomogeneous distribution of small local regions. We show, based neither on free‐volume nor on configurational entropy theories that the correlation volume V of such inhomogeneous regions isR [ΔH* (1−x)/RT]2{kBT4gΔκTg/〈 Δ2 ln τ〉}, where Δh* is the enthalpy of activation near the glass transition temperature Tg, x is the Narayanaswamy–Gardon nonlinear parameter, ΔκTg is the change in thermal conductivity at Tg, 〈Δ2 ln τ〉, describes how wide is the spectrum of relaxation times, and kB and R are the Boltzmann and the gas constants, respectively. The correlation length does not diverge at Tg. In fact, the correlation length at Tg for B2O3, glycerol, and PVAc are found to be approximately 1.27, 0.91, and 1.53 nm, respectively. Our results indicate, in agreement with Moynihan and Schroeder, that characteristics of nonexponential relaxation in glass forming liquids may be due to inhomogeneous domains whose size are ...

In a recent paper, Cutroni and Mandacini [J. Chem. Phys. 114, 7124 (2001)] measured sound velocities and absorption coefficients in m-toluidine by an ultrasonic technique. They reported velocities that differ from previous published data and attributed some of these discrepancies to a possible difference between the local temperature which actually prevails at the place where the velocity is determined in these previous measurements, and the real temperature of the liquid. We compare their results with other data and discuss their assumption.

We investigated the glass-forming ability of three Pd–Cu–Ni–P alloys with different compositions (Pd40Cu30Ni10P20, Pd42.5Cu27.5Ni10P20 and Pd42.5Cu30Ni7.5P20) under a continuous cooling condition. The lowest critical cooling rate for glass formation was determined to be 0.067 K/s for the Pd42.5Cu30Ni7.5P20 alloy. The melting behavior indicates that the 7.5% Ni alloy has the nearest eutectic composition of the three alloys. The exceptionally low critical cooling rate of below 0.1 K/s is attributed to the elimination of the primary crystallization that occurs due to off-eutectic composition.

The acoustic velocities and their pressure dependence of bulk Zr41Ti14Cu12.5Ni9Be22.5C1 metallic glass (MG) have been measured up to 0.5 GPa by using a pulse echo overlap method. The elastic constants and thermodynamic parameters as well as their pressure dependence of the MG have been determined. The obtained elastic constants were compared to that of other kinds of glasses. More information about the microstructure, elastic properties, and glass forming ability of the MG was obtained.

Extensive efforts have been made to develop metallic-glasses with large casting diameter. Such efforts were hindered by the poor understanding of glass formation mechanisms and the origin of the glass-forming ability (GFA) in metallic glass-forming systems. In this work, we have investigated relaxation dynamics of a model bulk glass-forming alloy system that shows the enhanced at first and then diminished GFA on increasing the percentage of micro-alloying. The micro-alloying did not have any significant impact on the thermodynamic properties. The GFA increasing on micro-alloying in this system cannot be explained by the present theoretical knowledge. Our results indicate that atomic caging is the primary factor that influences the GFA. The composition dependence of the atomic caging time or residence time is found to be well correlated with GFA of the system.

In this paper, we propose a new parameter for glass-forming ability (GFA) based on the combination of thermodynamic (stability of stable and metastable liquids by ΔTm = Tmmix − Tl and ΔTx = Tx − Tg, respectively) and kinetic (resistance to crystallization by Tx) aspects for glass formation. The parameter is defined as e = (ΔTm + ΔTx + Tx)/Tmmix without directly adding Tg while considering the whole temperature range for glass formation up to Tmmix, which reflects the relative position of crystallization curve in continuous cooling transformation diagram. The relationship between the e parameter and critical cooling rate (Rc) or maximum section thickness for glass formation (Zmax) clearly confirms that the e parameter exhibits a better correlation with GFA than other commonly used GFA parameters, such as ΔTx (=Tx − Tg), K (=[Tx − Tg]/[Tl − Tx]), ΔT*(=(Tmmix − Tl)/Tmmix), Trg (=Tg/Tl), and γ (=[Tx]/[Tl + Tg]). The relationship between the e parameter and Rc or Zmax is also formulated and evaluated in the st...

Zr65Cu17.5Ni10Al7.5 as well as Zr69.5Cu12Ni11Al7.5 belong to the best glass forming alloys known. Glass transition temperatures of melt‐spun ribbons are 372 and 360 °C, respectively. TEM and x‐ray analysis of samples annealed above the glass transition temperature exhibit the formation of quasicrystalline microstructures with small amounts of crystalline phases. The metastable icosahedral phase is primitive with a quasilattice constant a=0.253 nm; its composition as determined by EDX is close to Zr69.5Cu12Ni11Al7.5. In both glasses, growth of the quasicrystals has been observed to be time‐dependent (r∝t1/2), thus indicating a diffusion controlled transformation.

As an example of a novel class of glass‐forming liquid crystals, compound (I) was synthesized and characterized to possess a nematic mesophase between Tg and Tc as the pristine crystal was heated beyond its Tm followed by quenching to below room temperature. Differential scanning calorimetry (DSC) and x‐ray diffraction techniques were employed to investigate its morphological stability. It was found that the nematic mesophase persists upon annealing for a period of up to 22 h without the appearance of new phases. However, after annealing in the nematic regime over a longer period of time, thermally activated phase transformations were observed, resulting in a new crystalline phase plus the pristine crystalline phase based on DSC thermal transition data and x‐ray diffraction patterns.

Molecular dynamics simulation results are used to demonstrate the existence of a growing length in supercooled, fragile glass‐forming liquids. This length is the longest wavelength, propagating shear wave the fluid can support. Explicit results are reported for an equimolar soft‐sphere mixture. A possible connection between this length and the size of locally rigid clusters is discussed.

The viscosity of molten Ni80P20 was measured from 1143 to 1253 K by the capillary flow method. It can be described very well by the Vogel–Fulcher equation. When the viscosity is expressed in a reduced temperature scale which is defined as T/Tg where Tg is its glass transition temperature, it follows the principle of corresponding states, the same as other easy glass forming systems.

Thermal behaviors of liquid La-based bulk metallic glasses have been measured by using the dilatometer with a self-sealed sample cell. It is demonstrated that the strong glass forming liquid not only has the small thermal expansion coefficient but also shows the slow variation rate. Moreover, the strong glass former has relatively dense atomic packing and also small density change in the liquid state. The results suggest that the high glass forming ability of La-based metallic glasses would be closely related to the slow atomic rearrangements in liquid melts.

Gd55Al20Co20Ni5 bulk metallic glass (BMG) was synthesized by minor Ni substitution for Co in the Gd55Al20Co25 BMG in which excellent glass forming ability (GFA) and magneto-caloric effect were reported previously. The Gd55Al20Ni20Co5 amorphous rod has a similar GFA to the Gd55Al20Co25 BMG but exhibits better magnetic properties. The peak value of magnetic entropy change (−ΔSmpeak) of the Gd55Al20Co20Ni5 BMG is 9.8 Jkg−1 K−1. The field dependence of −ΔSmpeak follows a −ΔSmpeak∝H0.85 relationship. The adiabatic temperature rise of the rod is 4.74 K under 5 T and is larger than of other BMGs previously reported. The improved magnetic properties were supposed to be induced by the enhanced interaction between 4f electron in the rare-earth and 3d electron in the transition metal elements by means of a minor Ni substitution for Co.

We test the applicability of a living polymerization theory to describe cooperative string-like particle rearrangement clusters (strings) observed in simulations of a coarse-grained polymer melt. The theory quantitatively describes the interrelation between the average string length L, configurational entropy Sconf, and the order parameter for string assembly Φ without free parameters. Combining this theory with the Adam-Gibbs model allows us to predict the relaxation time τ in a lower temperature T range than accessible by current simulations. In particular, the combined theories suggest a return to Arrhenius behavior near Tg and a low T residual entropy, thus avoiding a Kauzmann “entropy crisis.”