Impact of Severe Deformation by HPT at Room Temperature on the Relaxation of the Glassy and the Supercooled Liquid States of PdNiP

2019 ◽  
Author(s):  
Afrouz Hassanpour ◽  
Sven Hilke ◽  
Sergiy V. Divinski ◽  
Gerhard Wilde
Keyword(s):  
Room Temperature ◽  
Supercooled Liquid ◽  
Severe Deformation ◽  
Liquid States

APPLICATION OF REED-VIBRATION MECHANICAL SPECTROSCOPY FOR LIQUIDS IN STUDYING LIQUID CRYSTALLIZATION

2013 ◽  
Vol 27 (21) ◽  
pp. 1350080 ◽  
Author(s):  
HENG-WEI ZHOU ◽  
LI-NA WANG ◽  
LI-LI ZHANG ◽  
YI-NENG HUANG
Keyword(s):  
Glass Transition ◽  
Room Temperature ◽  
Crystallization Process ◽  
Volume Fraction ◽  
Supercooled Liquid ◽  
Avrami Exponent ◽  
Dimethyl Phthalate ◽  
Mechanical Spectroscopy ◽  
Crystal Volume ◽  
Complex Young’S Modulus

By using the reed-vibration mechanical spectroscopy for liquids (RMS-L), we measured the complex Young's modulus of dimethyl phthalate (DP) during a cooling and heating circulation starting from room temperature at about 2 KHz. The results show that there is no crystallization in the cooling supercooled liquid (CSL) of DP, but a crystallization process in the heating supercooled liquid (HSL) after the reverse glass transition. Based on the measured modulus, crystal volume fraction (v) during the HSL crystallization was calculated. Moreover, the Avrami exponent (n) was obtained according to the JJMA equation and v data. In view of n versus temperature and v, the nucleation dynamics was analyzed, and especially, there has already existed saturate nuclei in DP HSL before the crystallization. Furthermore, the authors inferred that the nuclei are induced by the random frozen stress in the glass, but there is no nucleus in CSL. The above results indicated that RMS-L might provide a new way to measure and analyze the crystallization of liquids.

Correlation between effective activation energy and pre-exponential factor for diffusion in bulk metallic glasses

1999 ◽  
Vol 14 (8) ◽  
pp. 3200-3203 ◽  
Author(s):  
S. K. Sharma ◽  
F. Faupel
Keyword(s):  
Activation Energy ◽  
Metallic Glasses ◽  
Effective Activation Energy ◽  
Bulk Metallic Glasses ◽  
Supercooled Liquid ◽  
The Novel ◽  
Effective Activation ◽  
Exponential Factor ◽  
Liquid States ◽  
Fitting Parameters

The values of effective activation energy (Q) and pre-exponential factor (D0) reported in the literature for diffusion in the novel bulk metallic glasses, both in the glassy and the deeply supercooled liquid regions, are found to follow the same correlation as reported earlier in conventional metallic glasses, namely D0 = A exp(Q/B), where A and B are fitting parameters with values A = 4.8 × 10−19 m2 s−1 and B = 0.056 eV atom−1. A possible explanation for the observed values of A and B is given by combining an activation energy and a free volume term. The interpretation favors a cooperative mechanism for diffusion in the glassy and deeply supercooled liquid states.

scholarly journals Improve the Forming Ability of Al-Based Metallic Glass Under Ultrasonic Vibration at Room Temperature

2021 ◽  
Vol 8 ◽  
Author(s):  
Xiong Liang ◽  
Caitao Fan ◽  
Jianan Fu ◽  
Zehang Liu ◽  
Zhenxuan Zhang ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Ultrasonic Vibration ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Deformation Degree ◽  
Maximum Deformation ◽  
Primary Sample

In this work, a rapid and controllable ultrasonic vibration method for forming Al-based metallic glass at room temperature is proposed. This method can dramatically improve the forming ability of Al-based metallic glasses, which are virtually brittle at room temperature and have almost no supercooled liquid region at high temperatures. Under ultrasonic vibration, Al-based metallic glasses exhibited obvious plastic flow, with a maximum deformation degree up to 58% and an average deformation degree up to 43%. It is worth mentioning that no crystalline peaks were found on the X-ray diffraction patterns after deformation under ultrasonic vibration, and the mechanical properties remained the same as the primary sample. The present results provide a new approach for the deformation and forming of Al-based metallic glasses, which can significantly broaden their applications.

The Shear Modulus of Vit 1 in the Supercooled Liquid and Glassy State

2000 ◽  
Vol 644 ◽  
Author(s):  
Alijeet S. Bains ◽  
Craig A. Gordon ◽  
Andrew V. Granato ◽  
Alexander B. Lebedev ◽  
Marissa A. LaMadrid ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Specific Heat ◽  
Temperature Dependence ◽  
Condensed Matter ◽  
Glassy State ◽  
Supercooled Liquid ◽  
Constant Heating Rate ◽  
Fragility Parameter ◽  
Liquid States ◽  
Constant Heating

AbstractUsing a non-contact electromagnetic-acoustic transformation (EMAT) technique, we have measured the temperature dependence of the infinite frequency shear modulus of Vit 1 at constant heating rate in the glassy and supercooled liquid states. Values of the shear softening fragility parameter -dln(G/Gg/d(T/Tg) are compared with those obtainable from specific heat and viscosity measurements, using the interstitialcy theory of condensed matter states. There is overall agreement found between these independently measured values.

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