Crystallization and Nanocrystallization Kinetics of Fe-Based Amorphous Alloys

1999 ◽  
Vol 577 ◽  
Author(s):  
A. Hsiao ◽  
Z. Turgut ◽  
M.A. Willard ◽  
E. Selinger ◽  
D.E. Laughlin ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Crystallization Kinetics ◽  
Alloy System ◽  
Primary Crystallization ◽  
Avrami Equation ◽  
Secondary Crystallization ◽  
Scanning Calorimetry ◽  
Constant Heating ◽  
Kinetics Of ◽  
Calorimetry Data

ABSTRACTIn this work we describe crystallization kinetics as inferred from time-dependent magnetization studies and thermal analysis for an Allied Signal amorphous Fe-based METGLAS® 2605SA-1 alloy and a NANOPERM (Fe88Zr7B4Cu1) alloy. We illustrate and contrast several phenomena important to understanding crystallization kinetics in particular to the NANOPERM alloy system. In METGLAS® 2605SA-1 primary and secondary crystallization events are observed in differential scanning calorimetry data (DSC) at temperatures of 504 °C and 549 °C, respectively for data taken at a 10 °C/min scan rate. Both temperatures are greater than the Curie temperature of the amorphous alloy. For the NANOPERM alloy primary crystallization (as determined from differential thermal analysis (DTA)) occurs at 500 °C and secondary crystallization at 730 °C and M(t) at temperatures near the primary crystallization temperature is dominated (at short times < 1 hour) by the primary crystallization event. Using the Johnson-Mehl-Avrami equation for isothermal transformations and the Kissinger equation for constant heating transformations, we find corresponding models for the crystallization kinetics of the NANOPERM alloy.

Parameters characterizing the kinetics of the non-isothermal crystallization of polyamide 5,6 determined by differential scanning calorimetry

2014 ◽  
Vol 34 (4) ◽  
pp. 353-358 ◽  
Author(s):  
Yassir A. Eltahir ◽  
Haroon A.M. Saeed ◽  
Chen Yuejun ◽  
Yumin Xia ◽  
Wang Yimin
Keyword(s):  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Crystallization Rate ◽  
Degree Of Crystallinity ◽  
Avrami Equation ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics ◽  
Ozawa Model ◽  
Kinetic Crystallization ◽  
Kinetics Of

Abstract The non-isothermal crystallization behavior of polyamide 5,6 (PA56) was investigated by differential scanning calorimeter (DSC), and the non-isothermal crystallization kinetics were analyzed using the modified Avrami equation, the Ozawa model, and the method combining the Avrami and Ozawa equations. It was found that the Avrami method modified by Jeziorny could only describe the primary stage of non-isothermal crystallization kinetics of PA56, the Ozawa model failed to describe the non-isothermal crystallization of PA56, while the combined approach could successfully describe the non-isothermal crystallization process much more effectively. Kinetic parameters, such as the Avrami exponent, kinetic crystallization rate constant, relative degree of crystallinity, the crystallization enthalpy, and activation energy, were also determined for PA56.

scholarly journals Analysis of the rheological property and crystallization behavior of polylactic acid (Ingeo™ Biopolymer 4032D) at different process temperatures

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 702-709
Author(s):  
Hyeong Min Yoo ◽  
Su-Yeon Jeong ◽  
Sung-Woong Choi
Keyword(s):  
Rheological Property ◽  
Polylactic Acid ◽  
Crystallization Kinetics ◽  
Crystallization Behavior ◽  
Crystallization Rate ◽  
Avrami Equation ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics ◽  
Shear Rates ◽  
Kinetics Of

Abstract The aim of this study was to determine the rheological property and crystallization behavior of polylactic acid (PLA) with improved heat resistance (Ingeo™ Biopolymer 4032D) through investigation of the melt viscosity and crystallization kinetics of PLA at different process temperatures. The viscosity was measured using a rotational rheometer under conditions of shear rates of 0.01, 0.1, and 1/s. The obtained rheological data show that the viscosity tended to decrease slightly as the shear rate increases and decrease sharply as the temperature increases from 180°C to 210°C. To investigate the effect of the process temperature on the crystallization kinetics and final crystallinity of PLA, thermal analysis using isothermal differential scanning calorimetry (DSC) were also performed. The Avrami equation was successfully applied for the isothermal crystallization kinetics model. From crystallization temperature of 85°C to 120°C, we found that the Ingeo™ Biopolymer 4032D PLA had the fastest crystallization rate (t 1/2: 26.0 min) and the largest crystallinity (47.4%) at 100°C.

scholarly journals Morphology and crystallization kinetics of Rubber-modified Nylon 6 Prepared by Anionic In-situ Polymerization

2020 ◽  
Vol 27 (1) ◽  
pp. 204-215
Author(s):  
Hongkai Zhao ◽  
Dengchao Zhang ◽  
Yingshuang Li
Keyword(s):  
Crystallization Kinetics ◽  
In Situ Polymerization ◽  
Good Description ◽  
Nylon 6 ◽  
Avrami Equation ◽  
Infrared Analysis ◽  
Chain Segment ◽  
The Impact ◽  
Kinetics Of

AbstractIn this work, we modified nylon 6 with liquid rubber by in-situ polymerization. The infrared analysis suggested that HDI urea diketone is successfully blocked by caprolactam after grafting on hydroxyl of HTPB, and the rubber-modified nylon copolymer is generated by the anionic polymerization. The impact section analysis indicated the rubber-modified nylon 6 resin exhibited an alpha crystal form.With an increase in the rubber content, nylon 6 was more likely to generate stable α crystal. Avrami equation was a good description of the non-isothermal crystallization kinetics of nylon-6 and rubber-modified nylon-6 resin. Moreover, it is found that the initial crystallization temperature of nylon-6 chain segment decreased due to the flexible rubber chain segment. n value of rubber-modified nylon-6 indicated that its growth was the coexistence of two-dimensional discoid and three-dimensional spherulite growth. Finally, the addition of the rubber accelerated the crystallization rate of nylon 6.

scholarly journals Analysis of the Crystallization Kinetics and Thermal Stability of the Amorphous Mg72Zn24Ca4 Alloy

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3583
Author(s):  
Bartosz Opitek ◽  
Janusz Lelito ◽  
Michał Szucki ◽  
Grzegorz Piwowarski ◽  
Łukasz Gondek ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Crystallization Kinetics ◽  
Crystallization Process ◽  
Isothermal Annealing ◽  
Amorphous Structure ◽  
Avrami Equation ◽  
Temperature Phase ◽  
Scanning Calorimetry ◽  
Human Body Temperature ◽  
End Times

The aim of this study was to analyze the crystallization of the Mg72Zn24Ca4 metallic glass alloy. The crystallization process of metallic glass Mg72Zn24Ca4 was investigated by means of the differential scanning calorimetry. The glass-forming ability and crystallization are both strongly dependent on the heating rate. The crystallization kinetics, during the isothermal annealing, were modelled by the Johnson–Mehl–Avrami equation. Avrami exponents were from 2.7 to 3.51, which indicates diffusion-controlled grain growth. Local exponents of the Johnson–Mehl–Avrami equation were also calculated. In addition, the Mg phase—being the isothermal crystallization product—was found, and the diagram of the time–temperature phase transformation was developed. This diagram enables the reading of the start and end times of the crystallization process, occurring in amorphous ribbons of the Mg72Zn24Ca4 alloy on the isothermal annealing temperature. The research showed high stability of the amorphous structure of Mg72Zn24Ca4 alloy at human body temperature.

Effect of Arenga Pinnata “Ijuk” Fiber as Nucleating Agent on Crystallization Kinetics of Impact Polypropylene Copolymer

2018 ◽  
Vol 923 ◽  
pp. 56-60 ◽  
Author(s):  
Mochamad Chalid ◽  
Evana Yuanita ◽  
Ghiska Ramahdita ◽  
Jaka Fajar Fatriansyah
Keyword(s):  
Crystal Growth ◽  
Crystallization Kinetics ◽  
Nucleating Agent ◽  
Avrami Equation ◽  
Nucleating Agents ◽  
Impact Polypropylene Copolymer ◽  
Kinetics Of

Impact Polypropylene Copolymer (IPC) is one of the PP type which is widely used. IPC was made with addition of ethylene in PP which decreases PP crystallinity. Many efforts have been made to improve the properties of PP crystallinity by addition of nucleating agents. In this study, we use Arenga Pinnata “Ijuk” fiber as PP nucleating agent. In order to determine the effect of “Ijuk” fiber as nucleating agents in kinetics aspect, we used DSC measurement based on Avrami equation. The results showed that the addition of ijuk decreases crystallizationhalf timeand dimension of crystal growth which indicate the effects of “Ijuk” fiber as a nucleating agent.

scholarly journals Thermal Properties and Non-Isothermal Crystallization Kinetics of Poly (δ-Valerolactone) and Poly (δ-Valerolactone)/Titanium Dioxide Nanocomposites

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 452 ◽  
Author(s):  
Waseem Saeed ◽  
Abdel-Basit Al-Odayni ◽  
Abdulaziz Alghamdi ◽  
Ali Alrahlah ◽  
Taieb Aouak
Keyword(s):  
Titanium Dioxide ◽  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Three Dimensional ◽  
Degree Of Crystallinity ◽  
Simultaneous Occurrence ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics ◽  
The Stability ◽  
Kinetics Of

New poly (δ-valerolactone)/titanium dioxide (PDVL/TiO2) nanocomposites with different TiO2 nanoparticle loadings were prepared by the solvent-casting method and characterized by Fourier transform infra-red, differential scanning calorimetry, X-ray diffraction and scanning electron microscopy, and thermogravimetry analyses. The results obtained reveal good dispersion of TiO2 nanoparticles in the polymer matrix and non-formation of new crystalline structures indicating the stability of the crystallinity of TiO2 in the composite. A significant increase in the degree of crystallinity was observed with increasing TiO2 content. The non-isothermal crystallization kinetics of the PDVL/TiO2 system indicate that the crystallization process involves the simultaneous occurrence of two- and three-dimensional spherulitic growths. The thermal degradation analysis of this nanocomposite reveals a significant improvement in the thermal stability with increasing TiO2 loading.

scholarly journals Influence of Annealing Temperature on the Crystallization Kinetics of Fe82Si8B10 Amorphous Ribbon

2020 ◽  
Vol 11 (1) ◽  
pp. 107-112
Author(s):  
A Said Sikder ◽  
SD Nath ◽  
SS Sikder
Keyword(s):  
Crystallization Kinetics ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Amorphous Ribbon ◽  
Primary Crystallization ◽  
Soft Magnetic Materials ◽  
Power Transformers ◽  
Soft Magnetic ◽  
Potential Applications ◽  
Kinetics Of

Amorphous soft magnetic materials have significant potential applications in specialist power transformers and in inductive devices. With the composition of Fe82Si8B10, 82% of the transition metals Fe and about 18% of metalloid or glass-former elements like B and Si are strongly magnetic at room temperature and offer dynamic opportunities for engineering applications. The crystallization kinetics has been studied by differential thermal analysis (DTA). The sample was annealed in a controlled way in the temperature range of 350-450°C at constant annealing time one hour. The kinetics of primary crystallization α-Fe(Si) phase and secondary crystallization Fe2B phase was studied as affected due to temperature. The sample annealed at 350oC temperature is almost unchanged which is still lower than that of primary crystallization temperature but the same condition when sample annealed at 450°C completely shows that the primary crystallization α-Fe(Si) phase has vanished and crystallization event took place to a good extent. Journal of Engineering Science 11(1), 2020, 107-112

A comparative study on the effect of higher acrylate on cross-linkable PMMA used as environment friendly latexes

2020 ◽  
Vol 32 (2) ◽  
pp. 135-141
Author(s):  
Sweta Shukla
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Butyl Methacrylate ◽  
Cross Linking ◽  
Scanning Calorimetry ◽  
Environment Friendly ◽  
Glycol Diacrylate ◽  
Poly Propylene ◽  
Kinetics Of ◽  
Scanning Electron

The kinetics of emulsion polymerization of monomers methyl methacrylate (MMA)/ n-butyl methacrylate (BMA) was studied to investigate the effect of cross-linkable monomer poly(propylene glycol diacrylate) (PPGDA). The results showed that by the incorporation of PPGDA rate constant of reaction decreased. Fourier transform infrared spectroscopy and scanning electron microscope were used to characterize the synthesized polymers. The thermal analysis of samples was done by differential scanning calorimetry, and the results were compared by the previous studies with MMA/ n-butyl acrylate (BA) and MMA/2-ethylhexyl acrylate (EHA). The glass transition temperature ( T g) values show that the latexes prepared using BA and EHA as comonomer was suitable for binder purpose, but in the present study the T g is not suitable in case of BMA as higher acrylate comonomer. That may be due to more cross-linking in MMA-BMA-PPGDA. The results conclude that the BA and EHA can be used as the binder, but the use of BMA is limited for the binder in coating applications.

scholarly journals Non-Isothermal Crystallization Kinetics of Injection Grade PHBV and PHBV/Carbon Nanotubes Nanocomposites Using Isoconversional Method

2020 ◽  
Vol 4 (2) ◽  
pp. 52
Author(s):  
Thaís Larissa do Amaral Montanheiro ◽  
Beatriz Rossi Canuto de Menezes ◽  
Larissa Stieven Montagna ◽  
Cesar Augusto Gonçalves Beatrice ◽  
Juliano Marini ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Model Fitting ◽  
Polarized Light ◽  
Isoconversional Method ◽  
Degree Of Crystallinity ◽  
Gamma Aminobutyric Acid ◽  
Scanning Calorimetry ◽  
Kinetics Of

Carbon nanotubes (CNT)-reinforced polymeric composites are being studied as promising materials due to their enhanced properties. However, understanding the behavior of polymers during non-isothermal crystallization is important once the degree of crystallinity and crystallization processes are affected when nanoparticles are added to matrices. Usually, crystallization kinetics studies are performed using a model-fitting method, though the isoconversional method allows to obtain the kinetics parameter without assuming a crystallization model. Therefore, in this work, CNTs were oxidized (CNT-Ox) and functionalized with gamma-aminobutyric acid (GABA) (CNT-GB) and incorporated into a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) matrix. The influence of the addition and functionalization of CNT in the crystallization kinetics of PHBV was evaluated using the isoconversional method with differential scanning calorimetry (DSC), and by polarized light optical microscopy (PLOM) and Shore D hardness. The incorporation and functionalization of CNT into PHBV matrix did not change the Šesták and Berggren crystallization model; however, the lowest activation energy was obtained for the composite produced with CNT-GB, suggesting a better dispersion into the PHBV matrix. PLOM and Shore D hardness confirmed the results obtained in the kinetics study, showing the smallest crystallite size for CNT-containing nanocomposites and the highest hardness value for the composite produced with CNT-GB.

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