scholarly journals Synthesis and Properties of Bulk Metallic Glasses in Pd-Ni-P and Pd-Cu-P Alloys

1996 ◽  
Vol 455 ◽  
Author(s):  
Y. He ◽  
R. B. Schwarz
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Composition Range ◽  
Wide Composition Range ◽  
Upper Limit ◽  
Ternary Alloy Systems ◽  
The Difference ◽  
Thermal Stability Of

ABSTRACTBulk amorphous Pd-Ni-P and Pd-Cu-P alloy rods with diameters ranging from 7 to 25 mm have been synthesized over a wide composition range using a fluxing technique. For most bulk amorphous Pd-Ni-P alloys, the difference ΔT = Tx - Tg between the crystallization temperature Tx and the glass transition temperature Tg is larger than 90 K, while for bulk amorphous Pd-Cu-P alloys, ΔT varies from 27 to 73 K. Pd40Ni40P20 has the highest glass formability, and 300-gram bulk amorphous cylinders, 25 mm in diameter and 50 mm in length, can be easily produced. This size, however, is not an upper limit. The paper presents the glass formation ranges for both ternary alloy systems and data on the thermal stability of the amorphous alloys, as well as their specific heat, density, and elastic properties.

Thermal Stability of Bulk Metallic Glasses. Influence on Mechanical Properties

1998 ◽  
Vol 554 ◽  
Author(s):  
J. M. Pelletier ◽  
Y. Jacquemard ◽  
J. Perez ◽  
R. Perrier de la Bathie
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Glass Transition ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Atomic Mobility ◽  
Heating Rates ◽  
Characteristic Temperatures ◽  
Shear Elastic Modulus ◽  
Thermal Stability Of

AbstractTwo Zr-base bulk metallic glasses were investigated in the present work. DSC experiments were performed at different heating rates (dT/dt). Evolution of the characteristic temperatures, glass transition and onset of crystallisation, were determined as a function of dT/dt. Evolution of shear elastic modulus and internal friction are measured as a function of temperature and resulting microstructural evolution; these evolutions are related to variation of the atomic mobility.

Thermal Stability of Rapidly Quenched TI-NI-AL Amorphous Alloys

1985 ◽  
Vol 58 ◽  
Author(s):  
K. Aoki ◽  
K. Hiraga ◽  
T. Masumoto
Keyword(s):  
Thermal Stability ◽  
Amorphous Phase ◽  
Amorphous Alloys ◽  
Melt Spinning ◽  
Composition Range ◽  
Amorphous Matrix ◽  
Al Alloys ◽  
The Other ◽  
Molten State ◽  
Thermal Stability Of

ABSTRACTTi-Ni-Al alloys were rapidly quenched from a molten state by the melt spinning method. Three kinds of metastable phases, namely, amorphous,nonequilibrium and quasicrystalline phases are formed in these alloys. The amorphous phase is formed in the range of 35 to 70 at% Ti and 0 to 25 at% Al. The nonequilibrium phases are formed in the composition range of 25 to 33 at% Ti. On the other hand, fine quasicrystalline phases are distributed in the amorphous matrix of the Ti-rich alloys. Crystallization temperatures and the hardness of the amorphous alloys were also examined.

Bulk amorphous Pd–Ni–Fe–P alloys: Preparation and characterization

1999 ◽  
Vol 14 (5) ◽  
pp. 2107-2115 ◽  
Author(s):  
T. D. Shen ◽  
Y. He ◽  
R. B. Schwarz
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Molar Volume ◽  
Amorphous Alloys ◽  
Composition Range ◽  
Glass Transition Temperatures ◽  
Bulk Amorphous Alloys ◽  
The Difference ◽  
Quenching Method ◽  
Chemically Selective

Bulk amorphous alloys of PdxNiyFe80−x−yP20 (25 ≤ x ≤ 60, 20 ≤ y ≤ 55, x + y ≥ 60) were prepared by a flux-melting and water-quenching method. Seven-mm diameter glassy rods of Pd40Ni40−xFexP20 (0 ≤ x ≤ 20) were studied in greater detail. For these alloys, the difference between the crystallization and glass transition temperatures ranges from 102 K for x = 0 to 53 K for x = 20. In this composition range, the reduced glass transition temperature, Trg, ranges from 0.66 to 0.57. The change in density upon crystallization ranges from 0.24 ± 0.04% for x = 0 to 1.33 ± 0.24% for x = 10. The partial molar volume of Fe in amorphous Pd40Ni40−xFexP20 alloys is significantly larger than the molar volume of (metastable) fcc Fe. This, as well as a comparison with the molar volumes of crystalline compounds, suggests chemically selective Fe–Pd bonding in these glasses.

Bulk Metallic Glasses: Aluminum-Based

2019 ◽  
Author(s):  
B.J. Yang ◽  
J.H. Yao ◽  
J.Q. Wang ◽  
Y.S. Chao ◽  
E. Ma
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Thermal Properties ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Systematic Investigation ◽  
Glass Forming Ability ◽  
Atomic Cluster ◽  
Glass Forming ◽  
Thermal Stability Of

This paper details a systematic investigation of the formation of Al-based bulk metallic glasses, expanding on an earlier brief report.[] We discuss an approach for designing and predicting the best glass-forming composition in the Al–TM–RE systems, based on the atomic cluster packing model for the internal structure of the glass. The effects of additional elements in quaternary and quinary systems on the glass-forming ability and thermal stability of the glasses are also discussed. Three new compositions, Al86Ni6Y4.5Co2La1.5, Al86Ni7Y5Co1La1 and Al86Ni7Y4.5Co1La1.5, are capable of forming fully glassy rods of 1 mm in diameter; their glass transition and other thermal properties are systematically characterized.

Structural Stability and Elasticity in Zr-Based Bulk Metallic Glasses

2007 ◽  
Vol 561-565 ◽  
pp. 1391-1395 ◽  
Author(s):  
Shuo Zhang ◽  
T. Ichitsubo ◽  
Yokoyama Yoshihiko ◽  
K. Miyagi ◽  
Eiichiro Matsubara
Keyword(s):  
Thermal Stability ◽  
Metallic Glass ◽  
Bulk Modulus ◽  
Bulk Metallic Glass ◽  
Structural Stability ◽  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Coordination Numbers ◽  
Constituent Elements ◽  
Thermal Stability Of

The structure, thermal stability and elasticity of Zr50Cu40Al10 bulk metallic glass (BMG) have been investigated with reference to Zr70Cu30 and Zr70Cu20Al10 amorphous alloys. The thermal stability of Zr50Cu40Al10 is significantly enhanced in comparison compared with those of the others. The large total coordination numbers more than 11 around all constituent elements are observed in Zr50Cu40Al10. A change of the bulk modulus in the crystallization is extremely small in Zr50Cu40Al10. The present experimental results indicate that atoms in the Zr50Cu40Al10 glass are closely packed and its microstructure is fairly uniform. This results in the much higher thermal stability of Zr50Cu40Al10.

Thermal Behavior of Chalcogenide glasses Te90Se10 and Se90Te10

2015 ◽  
Vol 7 (02) ◽  
pp. 113-118
Author(s):  
Arvind Kumar Verma ◽  
Anchal Srivastava ◽  
R. K Shukla ◽  
K. C Dubey
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Glass Forming Ability ◽  
Scanning Calorimetry ◽  
Glass Forming ◽  
The Difference ◽  
Thermal Stability Of

In the present research work melt quenching method has been adopted to prepare the glassy Te-rich (Te90Se10) and Se-rich (Se90Te10 ) Chalcogenide at a pressure of 10-2 Torr with constant Temperature at 1000°C for 8 hours. Devitrification characteristics of the pure glassy Chalcogenide Te90Se10 and Se90Te90 were investigated by using Differential scanning Calorimetry (DSC) 4000 Perkin Elmer. All the measurements carried out at fixed heating rate 10 0C/min under non-isothermal conditions. The Glass transition temperature (Tg) and other thermal properties were examined by temperature modulated differential scanning Calorimetry at 40 oC to 445 oC. Glass transition temperature (Tg) represents the strength or rigidity of the glass structure. Tg affords valuable information on the thermal stability of the glassy state but Tg alone does not give any information on the glass forming tendency. The difference of the Peak crystallization temperature (Tp) and Glass transition temperature (Tg) is a strong indication of the thermal stability. The higher the value of Tc and Tg the greater is the thermal stability. Glass transition temperature (Tg=2160C) of Tellurium rich (Te90Se10) is more than Glass transition temperature (Tg=730C) of Selenium rich (Se90Te90) due to semi metallic nature of Tellurium. The difference of (Tp-Tg) is a strong indicator of both the thermal stability and Glass forming ability (GFA). Higher the value of (Tp-Tg), higher is the thermal stability and GFA because higher values of this difference indicate more kinetic resistance to the crystallization. Glass forming ability (GFA) and thermal stability of Te90Se10 is greater than Se90Te90. For memory and switching materials, glass thermal stability and GFA parameters are very important. Intensity of Se-rich (Se90Te10) is more than Te-rich (Te90Se10) and both samples are polycrystalline in nature.

Thermal Stability and Relaxation Processes of The Ti-Cu- and Ti-Ni-Based Metallic Glasses

1993 ◽  
Vol 321 ◽  
Author(s):  
Nikolay G. Babich ◽  
Nikolay N. Dashevsky ◽  
Olesja I. Nakonechna ◽  
Sergey L. Revo ◽  
Nikolay I. Zakharenko
Keyword(s):  
Thermal Stability ◽  
Magnetic Susceptibility ◽  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Relaxation Processes ◽  
Spin Moment ◽  
Temperature Range ◽  
Impurity Atoms ◽  
Temperature Dependences ◽  
Thermal Stability Of

ABSTRACTTemperature dependences of magnetic susceptibility for Ti-Cu- and Ti-Ni-based amorphous alloys have been obtained in the temperature range 300–850 K. All investigated alloys are shown to be Pauli paramagnets. Fe and Co impurity atoms possess zero localized moment due to effect of spin moment quenching. Relaxation processes were studied using thermopower measurements. It was shown the thermal stability of investigated alloys is determined predominantly by Nagel-Tauc electronic criterion.

The effect of methyl and methoxy substituents on dianilines for a thermosetting polyimide system

2020 ◽  
Vol 32 (7) ◽  
pp. 801-822 ◽  
Author(s):  
John J La Scala ◽  
Greg Yandek ◽  
Jason Lamb ◽  
Craig M Paquette ◽  
William S Eck ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Glass Transition ◽  
Elevated Temperature ◽  
Methyl Substituent ◽  
Glass Transition Temperatures ◽  
High Performing ◽  
Methoxy Substituent ◽  
Acidic Conditions ◽  
Thermal Stability Of

4,4′-Methylenedianiline (MDA) is widely used in high-temperature polyimide resins, including polymerization of monomer reactants-15. The toxicity of MDA significantly limits the manufacturability using this resin. Modifying the substitution and electronics of MDA could allow for the reduction of toxicity while maintaining the high-performing properties of the materials derived from the modified MDA. The addition of a single methyl substituent, methoxy substituent, location of these substituents, and location of the amine relative to the phenolic bridge were modified as were other non-aniline diamines. Various anilines were condensed with paraformaldehyde under acidic conditions to yield dianilines. These dianilines and diamines were reacted with nadic anhydride and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride in methanol to form the polyamic acid oligomers and heated at elevated temperature to form polyimide oligomers. It was found that the molecular weight of the oligomers derived from MDA alternatives was generally lower than that of MDA oligomers resulting in lower glass transition temperatures ( T gs) and degradation temperatures. Additionally, methoxy substituents further reduce the T g of the polymers versus methyl substituents and reduce the thermal stability of the resin. Methyl-substituted alternatives produced polyimides with similar T gs and degradation temperatures. The toxicity of the MDA alternatives was examined. Although a few were identified with reduced toxicities, the alternatives with properties similar to that of MDA also had high toxicities.

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