DSC Experimental Study for Crystallization Process of Amorphous Alloy

2012 ◽  
Vol 198-199 ◽  
pp. 14-18
Author(s):  
Cun Shan Xu
Keyword(s):  
Glass Transition ◽  
Metallic Glass ◽  
Crystallization Process ◽  
Heating Temperature ◽  
Liquid Region ◽  
Magnetic Alloys ◽  
Ordinary Temperature ◽  
Metal Processing ◽  
Technological Interest ◽  
Transition Temperature Increase

Bulk metallic glass (BMG) formers are multicomponent alloys that vitrify with remarkable ease during solidification. Technological interest in these materials has been generated by their unique properties, which often surpass those of conventional structural materials. The metastable nature of BMGs, however, has imposed a barrier to broad commercial adoption, particularly where the processing requirements of these alloys conflict with conventional metal processing methods. Research on the crystallization of BMG formers. In this paper, we fabricated metallic glass of Nd-based and carried out experimental research. This kind of metallic glass has shown a distinct glass transition and stable super-cooled liquid region. At the same time, we find the paramagnetic performance of Nd-based metallic glass is different from other hard magnetic alloys at ordinary temperature. The DSC experiment indicate that the glass transition temperature increase with the heating temperature.

An Experimental Study for Crystallization Characteristics of Nd-Based Alloy

2011 ◽  
Vol 268-270 ◽  
pp. 611-615
Author(s):  
Feng Yang ◽  
Zhi Hua Gao ◽  
Di Wang ◽  
Yang Liu
Keyword(s):  
Experimental Study ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Heating Temperature ◽  
Liquid Region ◽  
Magnetic Alloys ◽  
Ordinary Temperature ◽  
Transition Temperature Increase

The bulk metallic glass has received much attention from scientist and engineer. In this paper, we fabricated metallic glass of Nd-based and carried out experimental research. This kind of metallic glass has shown a distinct glass transition and stable super-cooled liquid region. At the same time, we find the paramagnetic performance of Nd-based metallic glass is different from other hard magnetic alloys at ordinary temperature. The DSC experiment indicate that the glass transition temperature increase with the heating temperature.

Crystallization Characteristic Study for Amorphous of Nd60Al10Cu20Ni10

2014 ◽  
Vol 556-562 ◽  
pp. 385-388
Author(s):  
Dong Man Yu ◽  
Yan Hui Hu ◽  
Di Wang ◽  
Xiao Jing Li
Keyword(s):  
Glass Transition ◽  
Metallic Glass ◽  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Heating Temperature ◽  
Liquid Region ◽  
Ordinary Temperature ◽  
Thermal Features ◽  
High Cooling Rates ◽  
Almost All

Since the first synthesis of an amorphous phase in Au-Si system from liquid, a great number of amorphous alloys have been prepared by rapid solidification. Almost all amorphous alloys require high cooling rates and a lot of studies have been carried out for these metallic glasses. In this study, metallic glass of Nd60Al10Cu20Ni10 have been fabricated, and experimental research was carried out to reflect thermal features. It indicates that the Nd-based amorphous has shown a distinct glass transition and stable super-cooled liquid region. The research results show that the paramagnetic performance of Nd60Al10Cu20Ni10 metallic glass is different from other hard magnetic alloys at ordinary temperature. From the DSC experiment, it is found that the glass transition temperature is increasing with the heating temperature.

scholarly journals Effects of Annealing on Enthalpy Recovery and Nanomechanical Behaviors of a La-Based Bulk Metallic Glass

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 579
Author(s):  
Ting Shi ◽  
Lanping Huang ◽  
Song Li
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Structural Relaxation ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Nanoindentation Measurement

Structural relaxation and nanomechanical behaviors of La65Al14Ni5Co5Cu9.2Ag1.8 bulk metallic glass (BMG) with a low glass transition temperature during annealing have been investigated by calorimetry and nanoindentation measurement. The enthalpy release of this metallic glass is deduced by annealing near glass transition. When annealed below glass transition temperature for 5 min, the recovered enthalpy increases with annealing temperature and reaches the maximum value at 403 K. After annealed in supercooled liquid region, the recovered enthalpy obviously decreases. For a given annealing at 393 K, the relaxation behaviors of La-based BMG can be well described by the Kohlrausch-Williams-Watts (KWW) function. The hardness, Young’s modulus, and serrated flow are sensitive to structural relaxation of this metallic glass, which can be well explained by the theory of solid-like region and liquid-like region. The decrease of ductility and the enhancement of homogeneity can be ascribed to the transformation from liquid-like region into solid-like region and the reduction of the shear transition zone (STZ).

Thermal, Mechanical, and Corrosive Behaviors of a Cu-Based Metallic Glass

2010 ◽  
Vol 146-147 ◽  
pp. 1491-1497 ◽  
Author(s):  
Wei Ke An ◽  
An Hui Cai ◽  
Xiang Xiong ◽  
Yong Liu ◽  
Yun Luo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Glass Transition ◽  
Transition Temperature ◽  
Metallic Glass ◽  
Elastic Strain ◽  
Passive Films ◽  
Liquid Region ◽  
Corrosion Rates ◽  
Onset Crystallization Temperature ◽  
Strain Fracture

The thermal, mechanical, and corrosive properties for Cu50Zr40Ti10 (at. %) metallic glass were also investigated. The glass transition temperature Tg, onset crystallization temperature TX, and under-cooled liquid region △TX are 624.4, 691.1, and 66.7 K, respectively. The elastic strain, fracture strength, and elastic modulus are 2.13 %, 2099.78 MPa, and 86.85 GPa, respectively. The corrosion rates in 1 M HCl, 1 M NaCl, and 0.5 M H2SO4 solutions open to air at 298 K are estimated to be about 0.4759, 0.1076, and 1.758×10-3 mm/year, respectively. The passive films can be observed in HCl and NaCl but not in H2SO4, the corrosion products in the former are looser than those in the latter, resulting in the better corrosion resistance in the latter than in the former.

Thermal Stability and Crystallization Kinetics of Ti40Zr10Cu34Pd14Sn2 Bulk Metallic Glass

2012 ◽  
Vol 188 ◽  
pp. 3-10 ◽  
Author(s):  
Mariana Calin ◽  
Mihai Stoica ◽  
Na Zheng ◽  
Xiao Rui Wang ◽  
Sergio Scudino ◽  
...  
Keyword(s):  
Activation Energy ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Crystallization Process ◽  
Primary Crystallization ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Scanning Calorimetry ◽  
Diffusion Controlled

In this work, the isochronal and isothermal activation energies for the primary crystallization process of Ti40Zr10Cu34Pd14Sn2bulk metallic glass have been studied by differential scanning calorimetry and determined using the Kissinger approach and the Johnson-Mehl-Avrami analysis, respectively. The activation energy for crystallization evaluated by the Kissinger method is 253 kJ/mol. Similar activation energy for crystallization was obtained from the viscosity measurements. The values of the differential Avrami exponent are also determined from the isothermal data. Assuming diffusion-controlled growth, it is shown that thermal treatment of the samples in the supercooled liquid region considerably influences the behavior of the nucleation rate during the crystallization process.

Structural changes of the metallic glass Zr65Al7.5Cu27.5 during glass transition and in the undercooled liquid region

1997 ◽  
Vol 82 (1) ◽  
pp. 155-162 ◽  
Author(s):  
H. Schumacher ◽  
U. Herr ◽  
D. Oelgeschlaeger ◽  
A. Traverse ◽  
K. Samwer
Keyword(s):  
Glass Transition ◽  
Metallic Glass ◽  
Structural Changes ◽  
Liquid Region ◽  
Undercooled Liquid

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.

Strong Liquid Behavior of Zr-Ti-Cu-Ni-Be Bulk Metallic Glass Forming Alloys

1996 ◽  
Vol 455 ◽  
Author(s):  
Ralf Busch ◽  
Andreas Masuhr ◽  
Eric Bakke ◽  
William L. Johnson
Keyword(s):  
Glass Transition ◽  
Melting Point ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Supercooled Liquid ◽  
Glass Transition Region ◽  
Glass Forming ◽  
Liquid Behavior ◽  
Metallic Liquids ◽  
Microscopic Origin

ABSTRACTThe viscosities of the Zr46.75Ti8.25Cu7.5Ni10Be27.5 and the Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass forming liquids was determined from the melting point down to the glass transition in the entire temperature range of the supercooled liquid. The temperature dependence of the viscosity in the supercooled liquid obeys the Vogel-Fulcher-Tammann (VFT) relation. The fragility index D is about 20 for both alloys and the ratio between glass transition temperature and VFT temperature is found to be 1.5. A comparison with other glass forming systems shows that these bulk metallic glass formers are strong liquids comparable to sodium silicate glass. Furthermore, they are the strongest among metallic glass forming liquids. This behavior is a main contributing factor to the glass forming ability since it implicates a higher viscosity from the melting point down to the glass transition compared to other metallic liquids. Thus, the kinetics in the supercooled liquid is sluggish and yields a low critical cooling rate for glass formation. The relaxation behavior in the glass transition region of the alloys is consistent with their strong glassy nature as reflected by a stretching exponent that is close to 0.8. The microscopic origin of the strong liquid behavior of bulk metallic glass formers is discussed.

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