Gibbs free energy for the crystallization of metallic glass-forming alloys from an undercooled liquid

2008 ◽  
Vol 88 (4) ◽  
pp. 239-249 ◽  
Author(s):  
H. Dhurandhar ◽  
T. L. Shanker Rao ◽  
K. N. Lad ◽  
A. Pratap
Keyword(s):  
Free Energy ◽  
Metallic Glass ◽  
Gibbs Free Energy ◽  
Undercooled Liquid ◽  
Glass Forming

Thermodynamics of The Pd43Ni10Cu27P20 Bulk Metallic Glass Forming Alloy

2003 ◽  
Vol 806 ◽  
Author(s):  
Masahiro Kuno ◽  
Ludi A. Shadowspeaker ◽  
Jan Schroers ◽  
Ralf Busch
Keyword(s):  
Heat Capacity ◽  
Free Energy ◽  
Metallic Glass ◽  
Specific Heat ◽  
Bulk Metallic Glass ◽  
Gibbs Free Energy ◽  
Specific Heat Capacity ◽  
Undercooled Liquid ◽  
Glass Forming ◽  
Crystalline Mixture

ABSTRACTThe thermodynamics of the bulk metallic glass forming Pd43Ni10Cu27P20 alloy were investigated with differential scanning calorimetry (DSC). The specific heat capacity of the undercooled liquid with respect to the crystalline mixture was measured in the DSC simultaneously with the enthalpy of crystallization over the entire supercooled liquid region. The enthalpy, entropy, and Gibbs free energy change between the liquid and the crystalline mixture was determined from the specific heat capacity data. The calculated enthalpy function closely matched the enthalpies of crystallization that were measured in the DSC, which verifies the validity of the thermodynamic model used. A small Gibbs free energy difference between undercooled liquid and crystalline mixture was found for decreasing temperature in Pd43Ni10Cu27P20 when compared to other glass forming alloys. This reflects a small driving force for crystallization when undercooling this alloy and is the main contributing factor for its high glass forming ability.

Thermodynamics of Te80Ge20 − x Pbx glass-forming alloys

1988 ◽  
Vol 3 (3) ◽  
pp. 570-575 ◽  
Author(s):  
L. Battezzati ◽  
A. L. Greer
Keyword(s):  
Free Energy ◽  
Specific Heat ◽  
Glass Forming Ability ◽  
Undercooled Liquid ◽  
Scanning Calorimetry ◽  
Entropy Of Fusion ◽  
Glass Forming ◽  
Crystal Phases ◽  
Solid Phases ◽  
Liquid And Solid Phases

The specific heat of liquid and solid phases and the heats of crystallization and fusion have been measured by differential scanning calorimetry (DSC) for a series of Te80Ge20 − x Pbx alloys (0≤x≤20). The enthalpy, entropy, and free energy of the undercooled liquid are quantitatively assessed with reference to the crystal phases. The available formulas for computing the free energy of the liquid are compared, and their relative merits are discussed. The glass transition temperature is shown to depend strongly on the ratio of the average excess specific heat of the liquid to the entropy of fusion. An anomaly in the liquid specific heat, which is particularly important for Te80Ge20 and Te80Ge15Pb5, leads to very good glass forming ability for these alloys; this is demonstrated by preparing amorphous samples by means of fluxing.

AC Modulation Calorimetry of Undercooled Liquid Ti34Zr11Cu47Ni8 and Zr57Nb5Ni12.6Al10Cu15.4: An MSL-1 Experiment Using TEMPUS

1998 ◽  
Vol 551 ◽  
Author(s):  
S.C. Glade ◽  
D.S. Lee ◽  
R. Wunderlich ◽  
W.L. Johnson
Keyword(s):  
Metallic Glass ◽  
Specific Heat ◽  
Radiative Cooling ◽  
Undercooled Liquid ◽  
Free Energies ◽  
Nucleation Kinetics ◽  
Glass Forming ◽  
Maximum Undercooling ◽  
Electrostatic Levitator ◽  
Kinetics Of

AbstractAn AC modulation calorimetry (ACMC) experiment was performed on two bulk metallic glass forming alloys, Ti34Zr11CU47Ni8 (VIT 101) and Zr57Nb5Ni12.6Al10Cu15.4(VIT 106) on the recent MSL-1 shuttle flight using the TEMPUS hardware. VIT 106 exhibited a maximum undercooling of 140 K in free radiative cooling, while VIT 101 exhibited a smaller undercooling of 50 K. Specific heat measurements were done in both the stable and undercooled liquid regions. These results will be combined with further ground-based measurements in an electrostatic levitator for modeling the nucleation kinetics of these alloys and for calculation of the free energies and entropies of the undercooled liquids in these systems.

Thermophysical Properties of Bulk Metallic Glasses in the Stable and Undercooled Liquid – A Microgravity Investigation

2000 ◽  
Vol 644 ◽  
Author(s):  
Hans-Jörg Fecht ◽  
Rainer K. Wunderlich ◽  
Stephen C. Glade ◽  
William L. Johnson
Keyword(s):  
Liquid Phase ◽  
Metallic Glass ◽  
Metallic Glasses ◽  
Thermophysical Properties ◽  
Short Range ◽  
Short Range Order ◽  
Undercooled Liquid ◽  
Pronounced Change ◽  
Glass Forming ◽  
Total Hemispherical Emissivity

AbstractThe thermophysical properties in the stable and undercooled liquid phase of a series of Zr- based metallic glass forming alloys have been investigated under the condition of reduced gravity on board spacelab. Properties measured included the specific heat capacity and the enthalpy of fusion, the electrical resistivity, the total hemispherical emissivity, and the thermal transport properties. Results for the bulk metallic glass forming alloys indicate a pronounced change in chemical short range order in the liquid phase as function of temperature.

Gibbs Free Energy Difference in Bulk Metallic Glass Forming Alloys

2008 ◽  
Vol 279 ◽  
pp. 91-96 ◽  
Author(s):  
Heena Dhurandhar ◽  
Kirit N. Lad ◽  
Arun Pratap ◽  
G.K. Dey
Keyword(s):  
Free Energy ◽  
Gibbs Free Energy ◽  
Activation Barrier ◽  
Energy Difference ◽  
Maximum Energy ◽  
Free Energy Difference ◽  
Glass Forming ◽  
Liquid Phases ◽  
Gibbs Free Energy Difference ◽  
Experimental Values

The Gibbs Free Energy Difference between the solid and liquid phases (DG) is related to nucleation frequency and has played an important role in predicting the glass forming ability (GFA) of multicomponent metallic alloys. This is due to the fact that the maximum energy for nucleus formation i.e. the activation barrier for nucleation has an inverse square relation with DG. The Gibbs Free Energy Difference of three multi-component bulk metallic glasses namely Mg65Cu25Y10, Zr57Cu15.4Ni12.6Al10Nb5 and Zr52.5Cu17.9Ni14.6Al10Ti5 have been evaluated using two new expressions. The results show that the DG values calculated assuming DCp to be constant lie closer to the experimental values for the Mg based system while in the case of two Zr based systems, DG computed using the hyperbolic variation of DCp show improved agreement with the experimental data.

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