Fast and direct determination of fragility in metallic glasses using chip calorimetry

The glass transition is relevant for performance definition in rubber products. For extrapolation to high-frequency behavior, time-temperature superposition is usually assumed, although most complex rubber compounds might be outside of its area of validity. Fast differential scanning calorimetry (FDSC) with cooling rates up to 1500 K/s and broadband dielectric spectroscopy (BDS) with frequencies up to 20 MHz are applied here to directly access both kinetics and dynamics of glass formation in a wide frequency range. For the first-time, the relation between the thermal vitrification and the dielectric relaxation is studied on vulcanized styrene-butadiene rubber, showing that both cooling rate and frequency dependence of its glass transition can be described by one single Vogel-Fulcher-Tammann-Hesse equation. The results indicate the validity of the Frenkel-Kobeko-Reiner equation. Another focus is the sample preparation of vulcanized elastomers for FDSC and BDS as well as the temperature calibration below 0 C.

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“…According to References 23, 62, and 63 the dynamic fragility, m , can be determined from the VFTH parameters by

m = \frac{B T}{{((), T - T_{V})}^{2}} .

…”

Section: Resultsmentioning

confidence: 99%

Kinetics of the glass transition of styrene‐butadiene‐rubber: Dielectric spectroscopy and fast differential scanning calorimetry

Lindemann

Schawe

Lacayo‐Pineda

2020

J of Applied Polymer Sci

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Section: Methodsmentioning

confidence: 99%

“…The concept of the limiting fictive temperature has already been applied to study the dynamic fragility and the glass transition in a wide range of cooling rates, e.g., polystyrene, [20,[22][23][24][25][26]30,32,76,77] polycarbonate, [29] polyether, [78] and other materials. [21,27,31,77,79,80] As shown with the three cases in Figure 4, any heating rate allows the determination of T f corresponding to the prevailing cooling. Consequently, the optimum heating rate for the instrument can be chosen.…”

Section: Analysis Strategymentioning

confidence: 96%

Cyclic Olefin Copolymers (COC)—Excellent Glass Formers with Low Dynamic Fragility

Zhang

Vadlamudi

Shaffer

et al. 2022

Macro Chemistry & Physics

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Applications of cyclic olefin copolymers (COC) are manifold, and developing a complete understanding of the characteristics of the glass transition behavior of these materials is essential to their processing and use in a variety of those applications. Fast scanning calorimetry is employed to investigate the glass transition of three commercial TOPAS COCs of different norbornene content between 37 and 54 mol% at cooling rates varying from 0.01 to 100 000 K s −1 . The glass transition temperatures as a function of cooling rate are determined as limiting fictive temperatures from reheating scans at 100 000 K s −1 . The data, covering seven orders of magnitude in cooling rate, allows the determination of the dynamic fragilities. The dynamic fragilities of TOPAS 6013, 6015, and 8007 are in the range of 50-60 and increase with increasing norbornene content. Compared to literature data of other polymers, the dynamic fragilities are rather low, and the COCs are classified as relatively strong glass formers. In other words, relating this information to processability, they have a relatively large "working range" and are classified as "long" glasses. Such classification, borrowed from glass making (blowing) technologies, may also help to describe the processability of polymeric glass formers in general.

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“…Mettler Toledo's fast scanning calorimeter, the Flash DSC 2+ launched in 2019, covers temperatures from − 100 to + 1000 °C and rates of − 40,000 to + 50,000 K s −1 and has great potential to study many materials in all fields of science. Metallic materials have been investigated with FSC in several contexts in materials science, including bulk metallic glasses (BMG) [15][16][17][18] and additive manufacturing [19][20][21] as well as nucleation and crystallisation [22,23].…”

Section: Introductionmentioning

confidence: 99%

Fast differential scanning calorimetry to mimic additive manufacturing processing: specific heat capacity analysis of aluminium alloys

Quick

Dumitraschkewitz

Schawe

et al. 2022

J Therm Anal Calorim

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Eutectic AlSi12, commonly used in casting and in additive manufacturing, is investigated with Fast Differential Scanning Calorimetry to determine the impact of different cooling rates from the liquid state upon the apparent specific heat capacity on subsequent heating. A heat flow correction strategy is developed and refined for the reliable and precise measurement of sample heat flow using chip sensors and assessed by the evaluation of results on pure (99.999%) aluminium. That strategy is then applied to the study of the AlSi12 eutectic alloy, and rate-dependent perturbations in the measured apparent specific heat capacity are discussed in terms of Si supersaturation and precipitation. Several cooling rates were implemented from − 100 to − 30,000 K s−1, and subsequent heating ranged from + 1000 to + 30,000 K s−1. After rapid cooling, a drop in AlSi12 apparent specific heat capacity is found on heating above ~ 400 °C; even at rates of + 10,000 K s−1, a result which has high relevance in metal additive manufacturing where similarly fast temperature cycles are involved. The Literature data, temperature modulated DSC and CALPHAD simulations on the heat capacity of AlSi12 are used to provide comparative context to the results from Fast Differential Scanning Calorimetry.

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Fast and direct determination of fragility in metallic glasses using chip calorimetry

Cited by 12 publications

References 30 publications

Kinetics of the glass transition of styrene‐butadiene‐rubber: Dielectric spectroscopy and fast differential scanning calorimetry

Kinetics of the glass transition of styrene‐butadiene‐rubber: Dielectric spectroscopy and fast differential scanning calorimetry

Cyclic Olefin Copolymers (COC)—Excellent Glass Formers with Low Dynamic Fragility

Fast differential scanning calorimetry to mimic additive manufacturing processing: specific heat capacity analysis of aluminium alloys

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