Crystallization Kinetics of Ti50Fe22Ni22Sn6 Amorphous Powders

2011 ◽  
Vol 108 ◽  
pp. 12-17
Author(s):  
Yu Ying Zhu ◽  
Qiang Li ◽  
Yun Hua He ◽  
Ge Wang ◽  
Xing Hua Wang
Keyword(s):  
Activation Energy ◽  
Amorphous Alloy ◽  
Crystallization Kinetics ◽  
Crystallization Process ◽  
Amorphous Powder ◽  
High Energy ◽  
Liquid Region ◽  
Amorphous Powders ◽  
Kinetics Of ◽  
Dsc Curves

The Ti50Fe22Ni22Sn6 amorphous powder was prepared by mechanical alloying with a high-energy planetary ball mill. Crystallization kinetics of the milled amorphous powders was investigated by DSC. Thermal analysis showed that when the heating rate increasing from 10K/min to 40K/min, the super-cooled liquid region of milled amorphous alloy increased from 93K to 110K. On the basis of the obtained DSC curves, the characteristic temperatures of the amorphous powders could be measured. The equations of Kissinger and Ozawa were used to calculate the crystallization activation energies of the milled amorphous alloy for comparing. The activation energy for the glass transition Eg had the maximum values of 650KJ/mol and 629KJ/mol calculated from Kissinger and Ozawa, respectively. In addition, the second crystallization process had a higher activation energy value comparing with the others crystallization events.

Ti50Fe25Ni25 Amorphous Alloy Prepared by Mechanical Alloying

2011 ◽  
Vol 327 ◽  
pp. 76-80
Author(s):  
Yu Ying Zhu ◽  
Qiang Li ◽  
Yun Hua He ◽  
Ge Wang ◽  
Xing Hua Wang
Keyword(s):  
Activation Energy ◽  
Amorphous Alloy ◽  
Mechanical Alloying ◽  
High Energy ◽  
Structural Features ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Crystallization Peak ◽  
Activation Energy Of Crystallization ◽  
Amorphous Alloy Powder

A new ternary Ti-based amorphous alloy, Ti50Fe25Ni25, is prepared by the mechanical alloying. The milling is performed in a high-energy planetary ball mill under argon atmosphere. Fully Ti50Fe25Ni25amorphous alloy powder is obtained after milled 160h. The milling speed is 300rpm and the weighs ratio of ball to powder is 10:1. The structural features are studied by X-ray diffraction and field emission scanning electron microscope, and the thermal stability is investigated by a differential scanning calorimeter. The super-cooled liquid region of the amorphous alloy increases from 98K to 119K as the heating rate increasing from 10K/min to 40K/min. The effective activation energy of crystallization is estimated with modified Kissinger’s plot. The initial crystallization activation energyEx1and the first crystallization peakEp1are 155.9KJ/mol and 188.5KJ/mol, respectively.

Crystallization Kinetics in Cu64.5Zr35.5 Binary Metallic Glass

2017 ◽  
Vol 727 ◽  
pp. 233-238 ◽  
Author(s):  
Qian Gao ◽  
Zeng Yun Jian ◽  
Jun Feng Xu ◽  
Man Zhu
Keyword(s):  
Activation Energy ◽  
Grain Growth ◽  
Crystallization Kinetics ◽  
Crystallization Process ◽  
Crystallization Kinetic ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Growth Activation ◽  
Local Activation Energy ◽  
Kinetics Of

The crystallization kinetics of melt-spun Cu64.5Zr35.5 amorphous alloy ribbons was investigated using differential scanning calorimetry (DSC) at different heating rates. Besides, the Kissinger and isoconversional approaches were used to obtain the crystallization kinetic parameters. As shown in the results, the activation energies for glass transition and crystallization process at the onset, peak and end crystallization temperatures were obtained by means of Kissinger equation to be 577.65 ± 34, 539.86 ± 54, 518.25 ± 20 and 224.84 ± 2 kJ/mol, respectively. The nucleation activation energy Enucleation is greater than grain growth activation energy Egrowth, indicating that the nucleation process is harder than grain growth. The local activation energy Eα decreases in the whole crystallization process, which suggests that crystallization process is increasingly easy.

scholarly journals Crystallization kinetics of K2O·TiO2·3GeO2 glass studied by DTA

2008 ◽  
Vol 40 (3) ◽  
pp. 333-338 ◽  
Author(s):  
S. Grujic ◽  
N. Blagojevic ◽  
M. Tosic ◽  
V. Zivanovic ◽  
J. Nikolic
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Particle Size ◽  
Differential Thermal Analysis ◽  
Crystallization Kinetics ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Samples ◽  
Kinetics Of

Crystallization kinetics of K2O?TiO2?3GeO2 glass was investigated by differential thermal analysis (DTA). Experiments were performed on powder samples with a particle size < 0.037 mm. The glass samples were heated at different rates in the temperature range 20-750?C. The kinetic parameters, activation energy for the crystallization process, Ec and Avrami exponent, n were calculated. Powder X-ray diffraction analysis (XRD) of crystallized glass reveals the presence of crystalline K2O?TiO2?3GeO2 indicating polymorphic crystallization with interface controlled crystal growth.

A New Ti-Based Amorphous Powder Synthesized by Mechanical Alloying

2012 ◽  
Vol 433-440 ◽  
pp. 642-645
Author(s):  
Yu Ying Zhu ◽  
Qiang Li ◽  
Yun Hua He ◽  
Ge Wang ◽  
Xing Hua Wang
Keyword(s):  
Crystal Structure ◽  
Amorphous Alloy ◽  
Mechanical Alloying ◽  
Ball Mill ◽  
Alloy Powder ◽  
Amorphous Powder ◽  
High Energy ◽  
Argon Atmosphere ◽  
Liquid Region ◽  
Amorphous Alloy Powder

A new quaternary amorphous alloy powder Ti50Fe22Ni22Sn6are prepared by mechanical alloying. The milling was performed under an argon atmosphere in a high-energy planetary ball mill. After milled 70h, fully amorphous Ti50Fe22Ni22Sn6powders can be obtained, with the condition of the milling speed, 300rpm, and the weighs ratio of ball to powder, 10:1. Crystal structure of the milled powders is investigated by XRD. Thermal analysis show that when the heating rate increasing from 10K/min to 40K/min, the super-cooled liquid region of milled amorphous alloy increased from 93K to 110K.

scholarly journals Non-Isothermal Crystallization Kinetics of Co67Fe4Cr7Si8B14 Amorphous Alloy

2012 ◽  
Vol 706-709 ◽  
pp. 1311-1317 ◽  
Author(s):  
S.A. Hasheminezhad ◽  
M. Haddad-Sabzevar ◽  
S. Sahebian
Keyword(s):  
Activation Energy ◽  
Amorphous Alloy ◽  
Crystallization Kinetics ◽  
Isothermal Crystallization ◽  
Frequency Factor ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Kinetics Parameters ◽  
Isothermal Crystallization Kinetics ◽  
Kinetics Of

Non-isothermal crystallization kinetics of Co67Fe4Cr7Si8B14amorphous ribbons was studied by differential scanning calorimetry (DSC) technique under 10, 20, 30, 40 and 80 °Cmin-1heating rates. It is found that Co67Fe4Cr7Si8B14amorphous alloy exhibits two-stage crystallization on heating. The two crystallization peaks shift to higher temperatures with increasing heating rate. The apparent activation energies (EC) for the first stage of crystallization were determined as 443.44 and 434.47 kJmol-1by using the Kissinger and Ozawa equations, respectively. Frequency factor (A) estimated to be 1.084×1026s-1using Kissinger equation. Kinetics parameters such as Crystallization exponent (n) and dimensionality of growth (Ndim) were determined using JMA (Johnson-Mehl-Avrami) method. Details of the nucleation and growth behaviours during the non-isothermal crystallization were studied in terms of local activation energy EC(x) by the OFW (Ozawa, Flynn and Wall) method. Also the activation energy for nucleation (En) and growth (Eg) separately estimated.

Crystallization kinetics of Zr60Cu25Ni5Al10 amorphous alloy

2020 ◽  
Author(s):  
Kurniawan ◽  
S. Firmansyah ◽  
R. D. Sulamet-Ariobimo ◽  
D. P. B. Aji
Keyword(s):  
Amorphous Alloy ◽  
Crystallization Kinetics ◽  
Kinetics Of

Morphology, Crystalline Structure and Isothermal Crystallization Kinetics of Polybutylene Terephthalate/Montmorillonite Nanocomposites

2005 ◽  
Vol 13 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Defeng Wu ◽  
Chixing Zhou ◽  
Xie Fan ◽  
Dalian Mao ◽  
Zhang Bian
Keyword(s):  
Activation Energy ◽  
Crystallization Kinetics ◽  
Crystallization Temperature ◽  
Isothermal Crystallization ◽  
Polymer Chains ◽  
Isothermal Crystallization Kinetics ◽  
Clay Particles ◽  
Nucleation Sites ◽  
Kinetics Of ◽  
Montmorillonite Nanocomposites

The melt intercalation method was employed to prepare poly(butylene terepathalate)/montmorillonite nanocomposites, and their microstructure was characterized by wide angle X-ray diffraction and transmission electron microscopy. The XRD results showed that the crystalline plane such as (010), (111), (100) was smaller than that of pristine PBT, which indicates that the crystallite size of PBT in the nanocomposites could be diminished by adding clay. Moreover, the isothermal crystallization kinetics of PBT and PBT/MMT nanocomposites was investigated by differential scanning calorimetry (DSC). During isothermal crystallization, the development of crystallinity with time was analysed by the Avrami equation. The results show that very small amounts of clay dramatically increased the rate of crystallization and high clay concentrations reduced the rate of crystallization at the low crystallization temperatures. At low concentrations of clay, the distance between dispersed platelets was large so it was relatively easy for the additional nucleation sites to incorporate surrounding polymer, and the crystal nucleus was formatted easily. However, at high concentrations of clay, the diffusion of polymer chains to the growing crystallites was hindered by large clay particles, despite the formation of additional nucleation sites by the clay layers. At the higher crystallization temperature, the crystallization of the nanocomposites was slower than that of the pure PBT under the experimental conditions, which means that with the increase in chains mobility at the high crystallization temperature, the crystal nuclei are harder to format, and the hindering effect of clay particles on the polymer chains was stronger than the nucleating effect of the layers. In addition, the activation energies of crystallization for PBT and its nanocomposites were calculated by the Arrhenius relationship, and the results showed that the nanocomposites with a low clay content had the lower activation energy values than PBT, while high amounts of clay increased the activation energy of PBT.

The Crystal Growth of Ti50Cu23Ni20Sn7 during the SPS Process

2012 ◽  
Vol 428 ◽  
pp. 190-195 ◽  
Author(s):  
Qiang Li ◽  
Yu Ying Zhu ◽  
Yun Hua He ◽  
Ge Wang ◽  
Xing Hua Wang
Keyword(s):  
Glass Transition ◽  
Amorphous Alloy ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Amorphous Powder ◽  
High Energy ◽  
Bulk Amorphous Alloy ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Amorphous Alloy Powder

Ti50Cu23Ni20Sn7 bulk amorphous alloy was prepared by mechanical alloying and spark plasma sintering. The milling was performed in a high-energy planetary ball mill. XRD showed that after milled 35h, fully amorphous powders can be obtained, under the condition of the milling speed, 300rpm, and the weighs ratio of ball to powder, 20:1. Thermal stability of the as-milled amorphous powder was determined by DSC at the heating rate of 40K/min. The glass transition Tg and the initial crystallization temperature Tx1 was 746K and 782K, respectively. Then, the obtained amorphous alloy powder was compacted by spark plasma sintering at the temperature of 753K, 763K, 773K, 783K and 793K under the compress of 500Mpa. Crystal structure and the morphology of the sintered samples were investigated by XRD and SEM, respectively. When sintered near the glass transition temperature, the SPS sintered samples remained complete amorphous, crystalline peak did not appear in the XRD curves. As the sintering temperature increased, the crystalline phases in the sample began to increase. It was shown that when sintered at 753K and 763K, the samples had fewer defects, and it was completely amorphous alloy. When the sintering temperature increased to 773K, more defects appeared, including point-like defects and disc-shaped defects. The disc-shaped defect was widespread in the specimens sintered at 783K and 793K.

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