Non-Isothermal Crystallization Behavior in Zr55Cu30Ni5Al10 Bulk Metallic Glass

A Zr55Cu30Ni5Al10 bulk amorphous alloy was prepared by using copper mold suction casting and the X-ray diffractometer (XRD) was utilized to determine its structure. The non-isothermal crystallization behavior of the amorphous alloy was studied via a differential scanning calorimeter (DSC) by Kissinger and Ozawa methods. The results showed that all the thermodynamic parameters move to higher temperatures with increasing heating rates. The activation energies for crystallization calculated by Kissinger and Ozawa method are 291.27 and 288.53 kJ/mol, respectively. With the increase of heating rate, the rate of x vs. T descends. The crystallization mechanism is typical nucleation and growth of crystalline grains, among which the latter dominates the total crystallization process.

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An Investigation toward the Nano-Crystallization of Fe55Cr18Mo7B16C4 Bulk Amorphous Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.383-390.3858 ◽

2011 ◽

Vol 383-390 ◽

pp. 3858-3862

Author(s):

S. Ahmadi ◽

H.R. Shahverdi ◽

S.S. Saremi

Keyword(s):

Amorphous Alloy ◽

Crystallization Process ◽

Three Dimensional ◽

Bulk Amorphous Alloy ◽

Differential Scanning Calorimetric ◽

X Ray Diffraction ◽

Heating Rates ◽

Diffusion Controlled ◽

Average Size ◽

Dsc Curves

Nano- crystallization of Fe55Cr18Mo7B16C4 bulk amorphous alloy has been analyzed by X- ray diffraction, differential scanning calorimetric test, and TEM observations in this research. In practice, crystallization and growth mechanism were evaluated using DSC tests in four different heating rates (10, 20, 30, 40 K/min) and kinetic models. A two -step crystallization process was observed in the alloy in which α – Fe, Fe23B6, and Fe3C phases were crystallized in the structure after annealing process. In addition, activation energy for the first step of crystallization process (i.e. α – Fe phase) was measured to be 276 (kj/mol) and 290 (kj/mol) according to Kissinger and Ozawa models respectively. Avrami exponent calculated from DSC curves was 2 and a three -dimensional diffusion controlled mechanism with decreasing nucleation rate was observed in the alloy. Further, it is known from the TEM observations that crystalline α – Fe phase nucleated in structure of the alloy in an average size of 10 nm and completely mottled morphology.

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Non-Isothermal Crystallization Kinetics of Poly(Ethylene Glycol)–Poly(l-Lactide) Diblock Copolymer and Poly(Ethylene Glycol) Homopolymer via Fast-Scan Chip-Calorimeter

Polymers ◽

10.3390/polym13071156 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1156

Author(s):

Dejia Chen ◽

Lisha Lei ◽

Meishuai Zou ◽

Xiaodong Li

Keyword(s):

Ethylene Glycol ◽

Heterogeneous Nucleation ◽

Isothermal Crystallization ◽

Crystallization Process ◽

Poly Ethylene Glycol ◽

Ozawa Method ◽

Isothermal Crystallization Kinetics ◽

Fast Cooling ◽

Poly Ethylene ◽

Kinetics Of

The non-isothermal crystallization kinetics of double-crystallizable poly(ethylene glycol)–poly(l-lactide) diblock copolymer (PEG-PLLA) and poly(ethylene glycol) homopolymer (PEG) were studied using the fast cooling rate provided by a Fast-Scan Chip-Calorimeter (FSC). The experimental data were analyzed by the Ozawa method and the Kissinger equation. Additionally, the total crystallization rate was represented by crystallization half time t1/2. The Ozawa method is a perfect success because secondary crystallization is inhibited by using fast cooling rate. The first crystallized PLLA block provides nucleation sites for the crystallization of PEG block and thus promotes the crystallization of the PEG block, which can be regarded as heterogeneous nucleation to a certain extent, while the method of the PEG block and PLLA block crystallized together corresponds to a one-dimensional growth, which reflects that there is a certain separation between the crystallization regions of the PLLA block and PEG block. Although crystallization of the PLLA block provides heterogeneous nucleation conditions for PEG block to a certain extent, it does not shorten the time of the whole crystallization process because of the complexity of the whole crystallization process including nucleation and growth.

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Small angle X-ray scattering research of the relaxation and crystallization process in Cu60Zr30Ti10 amorphous alloy

Acta Physica Sinica ◽

10.7498/aps.55.6673 ◽

2006 ◽

Vol 55 (12) ◽

pp. 6673

Author(s):

Cheng Wei-Dong ◽

Sun Min-Hua ◽

Li Jia-Yun ◽

Wang Ai-Ping ◽

Sun Yong-Li ◽

...

Keyword(s):

Amorphous Alloy ◽

Small Angle ◽

Crystallization Process ◽

X Ray ◽

X Ray Scattering ◽

Ray Scattering

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Comparative study of the crystallization behavior and morphologies of carbon and glass fiber reinforced poly(ether ether ketone) composites

Polymers and Polymer Composites ◽

10.1177/0967391120965102 ◽

2020 ◽

pp. 096739112096510

Author(s):

Pan Wang ◽

Qing Lin ◽

Yaming Wang ◽

Chuntai Liu ◽

Changyu Shen

Keyword(s):

Carbon Fiber ◽

Glass Fiber ◽

Isothermal Crystallization ◽

Crystallization Behavior ◽

Unit Cell ◽

Fiber Reinforced ◽

Scanning Calorimetry ◽

Avrami Model ◽

X Ray ◽

Glass Fiber Reinforced

This work aims to perform a systematic investigation on the crystallization behavior and morphologies of carbon and glass fiber reinforced PEEK. The nonisothermal and isothermal crystallization behavior was investigated by differential scanning calorimetry (DSC). The resultant morphologies were assessed by wide angle X-ray diffraction (WAXD), small angle X-ray scattering (SAXS), and polarized optical microscopy (POM) to provide details on spherulitic level, crystalline structure at unit cell, and lamellar levels. It was found that the crystallization ability of carbon fiber filled PEEK was better than that of neat PEEK, while the behavior of glass fiber filled PEEK was in an opposite trend. The incorporation of carbon fiber (or glass fiber) led to a looser packing of the unit cell or a less crystal perfection of PEEK but did not change its crystal form as well as its long period of lamellae. The isothermal crystallization kinetics was analyzed by the Avrami model, suggesting that the crystallization mechanism of carbon fiber filled PEEK was different from that of neat PEEK and its glass fiber filled composites. Nevertheless, the POM results showed that fiber-induced transcrystallization in PEEK matrix was not evidenced for either carbon or glass fiber filled PEEK. Finally, the effect of carbon and glass fiber on the crystallization of PEEK matrix was discussed to some extent.

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Nucleation and growth characteristics of amorphous FeSiB(Cu)(Nb) alloys during isothermal crystallization process

Materials Science and Engineering A ◽

10.1016/0921-5093(94)90876-1 ◽

1994 ◽

Vol 181-182 ◽

pp. 1419-1422 ◽

Cited By ~ 25

Author(s):

Fei Zhou ◽

Kai-Yuan He ◽

Man-Ling Sui ◽

Zu-Han Lai

Keyword(s):

Isothermal Crystallization ◽

Crystallization Process ◽

Nucleation And Growth ◽

Growth Characteristics

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The Crystallization Research on the Zr-Based Bulk Metallic Glasses by Ion Thinning

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.887-888.116 ◽

2014 ◽

Vol 887-888 ◽

pp. 116-120

Author(s):

Ying Liang Bai ◽

Lian Long He

Keyword(s):

Electron Microscope ◽

Amorphous Alloy ◽

Transmission Electron Microscope ◽

Metallic Glasses ◽

Bulk Amorphous Alloy ◽

Edge Region ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Nickel Crystals

Transmission Electron Microscope (TEM) and X-Ray Diffraction (XRD) were used to investigate crystallization of the Zr70Cu8Ti7Ni15 bulk amorphous alloy, the results show that the edge region of BMGs sample produces nanosize Nickel crystals using the method of the ion thinning to make the TEM sample. The quantity of nanocrystals is proportional to the time of ion thinning and they are not residual crystals in the BMGs.

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Diffusion-Controlled Nanocrystallization of the Fe73.5Cu1Nb3Si15.5B7 Finemet Amorphous Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.570.120 ◽

2008 ◽

Vol 570 ◽

pp. 120-125

Author(s):

R.M. Ribeiro ◽

R.S. de Biasi ◽

D.R. dos Santos ◽

Dílson S. dos Santos

Keyword(s):

Differential Scanning Calorimetry ◽

Amorphous Alloy ◽

Small Angle ◽

Nucleation And Growth ◽

Amorphous Metallic Alloy ◽

Scanning Calorimetry ◽

X Ray ◽

X Ray Scattering ◽

Diffusion Controlled

Crystallization of the amorphous metallic alloy Fe73.5 Cu1Nb3 Si8.5 B14 was investigated by ferromagnetic resonance (FMR), small angle in situ X-ray scattering (SAXS/WAXS) and differential scanning calorimetry (DSC). Only one crystalline phase was observed by WAXS and only one peak was observed by DSC. The activation energies, calculated from FMR and DSC data, were 287 kJ.mol-1 and 313.4 kJ.mol-1, respectively. The values calculated for the Avrami exponent were 0.98 (FMR) and 1.4 (DSC). These values correspond to different mechanisms of nucleation and growth; however, the SAXS /WAXS results suggest that the dominant mechanisms are nucleation and growth of crystals from small dimensions.

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