Non-Newtonian viscous flow in soda-lime-silica glass at forming and annealing temperatures

Simmons, Joseph H.; Ochoa, Romulo; Simmons, Kelly D.; Mills, J. J.

doi:10.1016/0022-3093(88)90325-0

Cited by 74 publications

(49 citation statements)

References 6 publications

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“…The data of Simmons et al, (1988), Manns & Bruckner (1988) and Webb & Dingwell (1990a, b) demonstrate that the occurrence of non-Newtoni an viscosity is scaled to the low strain rate, re laxed, Newtonian shear viscosity of the liquid. Although this simplifies the composition-depend ence of relaxation in silicate melts, it does not remove it.…”

Section: Rhyolitic Behaviormentioning

confidence: 94%

Relaxation in silicate melts

Dingwell¹,

Webb²

1990

ejm

426

253

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Abstract:The glass transition is a kinetic barrier that divides the behavior of silicate melts into two types, liquid and glassy. Liquid behavior is the equilibrium response of a melt to an applied perturbation, resulting in the determination of an equilibrium liquid property. The equilibrium may be stable (superliquidus) or metastable (subliquidus). Glassy behavior occurs when the timescale of the perturbation is too short for melt equilibration. This can occur when the frequency of an applied sinusoidal perturbation is too high or when the observation time of an experiment is too short. The time-or frequency-dependent response of the structure and properties of a melt to a perturbation is termed relaxation. Liquid and glassy behavior are relaxed and unrelaxed behavior, respectively.Linear viscoelastic theory provides mechanical models for the prediction of the isothermal transition from liquid to glassy behavior. A simple series combination of Hookean spring and Newtonian dashpot (a Maxwell element) is capable of predicting the timescale corresponding to the glass transition from the ratio of the relaxed viscosity to the infinite frequency elastic modulus. We review some experimental work on silicate melts that can be used to constrain the location of the glass transition in time-temperature space at 1 atm pressure (e.g., ultrasonic wave propagation, fiber elongation, torsional testing, scanning calorimetry).The microscopic origin of the glass transition in silicate melts is related to the exchange ofSi-O bonds. Recent" Si NMR work indicates that the Si-O bond exchange frequency matches the timescale of the glass transition. This explains the Newtonian viscosity of silicate liquids. No extended species (e.g., "polymers") can exist at higher temperatures and longer timescales than the lifetime of the fundamental Si-O bond. Silicate melts, however, become non-Newtonian as the strain rate approaches the equilibration rate of the Si-O bonds. Such a correlation between Si-O bond exchange and the viscous flow mechanism, in turn, explains the success of the Eyring relationship in relating high temperature oxygen and silicon self-diffusion to viscosity.Knowledge of the structural relaxation timescale is important in extracting equilibrium information from studies of the structure and properties of quenched glasses. Quench rate-dependent speciation data for glasses imply a temperature-dependence of the species equilibrium in the liquid state. Estimation of the relaxation times associated with the quench rates allows reconstruction of the temperature-dependence of homogeneous equilibria in liquids.Experimental work on silicate melts should consider the location of the experimental method in time-temperature space, with respect to the glass transition. Diffusivity measurements, for example, are influenced by the glass transition. When the duration of a diffusivity experiment crosses the volume relaxation time, an inflection in the temperature-dependence of diffusivity of cations is observed. A second "transition" in diff...

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Section: Rhyolitic Behaviormentioning

confidence: 94%

Relaxation in silicate melts

Dingwell¹,

Webb²

1990

ejm

426

253

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“…[1][2][3] Second, in the nonlinear response regime, glassy fluids generally exhibit highly viscous non-Newtonian flow close to (but above) T g even if they are low-molecularweight fluids. 4 In such fluids, ifγ > τ −1 α , atomic rearrangements are induced not by thermal agitations but by externally applied shear. [5][6][7] In chain systems without entanglements, on one hand, shear thinning occurs at sufficiently high (but sometimes unrealistically large) shear rates due to chain elongation.…”

Section: G(t) = G G (T) + G R (T) (12)mentioning

confidence: 99%

“…In Fig.7(b), we also plot the structure factor in the q x -q y plane (q z = 0), 4) which is proportional to the scattering intensity from labeled chains in shear. 37 In these figures θ is the relative angle of the ellipses with respect to the y (shear gradient) direction.…”

Section: Steady State Behavior In Shear Flowmentioning

confidence: 99%

Dynamics and rheology of a supercooled polymer melt in shear flow

Yamamoto

Ōnuki

2002

The Journal of Chemical Physics

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Using molecular dynamics simulations, we study dynamics of a model polymer melt composed of short chains with bead number N = 10 in supercooled states. In quiescent conditions, the stress relaxation function G(t) is calculated, which exhibits a stretched exponential relaxation on the time scale of the α relaxation time τα and ultimately follows the Rouse dynamics characterized by the time τR ∼ N 2 τα. After application of shearγ, transient stress growth σxy(t)/γ first obeys the linear growth t 0 dt ′ G(t ′ ) for strain less than 0.1 but saturates into a non-Newtonian viscosity for larger strain. In steady states, shear-thinning and elongation of chains into ellipsoidal shapes take place for shearγ larger than τ −1 R . In such strong shear, we find that the chains undergo random tumbling motion taking stretched and compact shapes alternatively. We examine the validity of the stressoptical relation between the anisotropic parts of the stress tensor and the dielectric tensor, which are violated in transient states due to the presence of a large glassy component of the stress. We furthermore introduce time-correlation functions in shear to calculate the shear-dependent relaxation times, τα(T,γ) and τR(T,γ), which decrease nonlinearly as functions ofγ in the shear-thinning regime.

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“…In contrast, the glass science literature contains several examples of the non-Newtonian behavior of silicate glasses (Li and Uhlmann 1970;Simmons et al 1982;Manns and Brfickner 1988;Simmons et al 1988). Using viscoelastic models (Tool 1948;Narayanaswamy 1971;Scherer 1984), the effects of thermal and stress history on the physical properties of silicate melts have been modeled and compared with volume and shear relaxation studies (Ritland 1954;Kurkjian 1963;Mills 1974;Larsen et al 1974;Perez et al 1981).…”

Section: Introductionmentioning

confidence: 99%

The onset of non-Newtonian rheology of silicate melts

1990

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Abstract. The viscoelastic behavior of silicate melts has been measured for a range of compositions (NaA1Si308, NaCaAlSi2OT, CaMgSi206, Li2Si409, Na2Si409, K2Si409, Na2Si3OT, K2Si307 and Na2Si2Os) using the fiber elongation method. All compositions exhibit Newtonian behavior at low strain-rates, but non-Newtonian behavior at higher strain-rates, with strain-rate increasing faster than the applied stress. The decrease in shear viscosity observed at the high strain-rates ranges from 0.3 to 1.6 loglo units (Pa s). The relaxation strain-rates, ~relax, of these melts have been estimated from the low strain-rate, Newtonian, shear viscosity, using the Maxwell relationship; +rel,x = r -1 = (rls/G~) -1. For all compositions investigated, the onset of non-Newtonian rheology is observed at strain-rates 2.5 _+ 0.5 orders of magnitude less than the calculated relaxation strain-rate. This difference between the non-Newtonian onset and the relaxation strain-rate is larger than that predicted by the single relaxation time Maxwell model. Normalization of the experimental strain-rates to the relaxation strain-rate predicted from the Maxwell relation, eliminates the composition-and temperature-dependence of the onset of non-Newtonian behavior. The distribution of relaxation in the viscoelastic region appears to be unrelated to melt chemistry. This conclusion is consistent with the torsional, frequency domain study of Mills (1974) which illustrated a composition-invariance of the distribution of the imaginary component of the shear modulus in melts ~ on the Na20-SiO2 join. The present, time domain study of viscoelasticity contrasts with frequency domain studies in terms of the absolute strains employed. The present study employs relatively large total strains (up to 2). This compares with typical strains of l 0 -8 in ultrasonic (frequency domain) studies. The stresses used to achieve the strain-rates required to observe viscoelastic behavior in this study approach the tensile strength of the fibers with the result that some of our experiments were terminated by fiber breakage. Although the breakage is unrelated to the observation of non-Newtonian viscosity, their close proximity in this and earlier studies suggests that brittle failure of igneous melts, may, in general, be preceded by a period of non-Newtonian rheology. 1, IntroductionNumerous investigations of the rheology of silicate melts at super-liquidus temperatures have demonstrated that the relationship between stress and strain in molten silicates is Newtonian, i.e. the strain-rate is linearly proportional to the applied stress (Bockris et al. 1955;Scarfe et al. 1983;Dingwell et al. 1985). Viscosity is a state variable and thus a strain-rate independence of viscosity implies that the thermodynamic state of the melt is independent of applied stress and the resultant strain-rate. Thus the observation of Newtonian viscosity simplifies considerably the thermodynamic description of silicate melts.In contrast, the glass science literature contains several examples of the non-New...

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Non-Newtonian viscous flow in soda-lime-silica glass at forming and annealing temperatures

Cited by 74 publications

References 6 publications

Relaxation in silicate melts

Relaxation in silicate melts

Dynamics and rheology of a supercooled polymer melt in shear flow

The onset of non-Newtonian rheology of silicate melts

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