Quenched-in Free Volume Vf, Deformation-induced Free Volume, the Glass Transition Tg and Thermal Expansion in glassy ZrNbCuNiAl measured by Time-resolved Diffraction in Transmission

2003 ◽  
Vol 806 ◽  
Author(s):  
A. R. Yavari ◽  
M. Tonegaru ◽  
N. Lupu ◽  
A Inoue ◽  
E. Matsubara ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Glass Transition ◽  
Free Volume ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Time Resolved ◽  
X Ray ◽  
Excess Free Volume ◽  
Rapidly Solidified

ABSTRACTUsing high-precision X-ray dilatometry, we have succeeded in directly measuring excess quenched-in free-volume Vf in metallic glasses. The method was applied to the very easy glass forming Zr57Nb5Cu15.4Ni12.6Al10 (Vit 106). The annealing out of the order of 0.5% free volume was observed during heat treatment of rapidly solidified glassy ribbons. Excess free volume was also generated by heavy deformation and observed to anneal out during heat treatment. Once the excess free volume anneals out, the glass transition Tg appears clearly as a break in the x-ray dilatation curves as the glass goes over to the supercooled liquid region prior to crystallization at Tx.

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).

Comments on “Fabrication of ternary Mg–Cu–Gd bulk metallic glass with high glass-forming ability under air atmosphere” [H. Men and D.H. Kim, J. Mater. Res. 18, 1502 (2003)]

2004 ◽  
Vol 19 (2) ◽  
pp. 427-428 ◽  
Author(s):  
Z.P. Lu ◽  
C.T. Liu
Keyword(s):  
Glass Transition ◽  
Metallic Glasses ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Glass Forming Ability ◽  
Bulk Amorphous Alloy ◽  
Liquid Region ◽  
Glass Forming ◽  
Air Atmosphere ◽  
Acta Mater

A new Mg-based bulk amorphous alloy (i.e., Mg65Cu25Gd10) has successfully been developed by Men and Kim [H. Men and D.H. Kim, J. Mater. Res. 18, 1502 (2003)]. They showed that this alloy exhibits significantly improved glass-forming ability (GFA) in comparison with Mg65Cu25Y10 alloy. However, this improved GFA cannot be indicated by the supercooled liquid region ΔT and the reduced glass-transition temperature Trg. As shown in the current comment, the new parameter γ, Tx/(Tg + Tl) defined in our recent papers [Z.P. Lu and C.T. Liu, Acta Mater. 50, 3501 (2002); Z.P. Lu and C.T. Liu, Phys. Rev. Lett. 91, 115505 (2003)] can well gauge GFA for bulk metallic glasses, including the current Mg-based alloys.

scholarly journals Structural Study of Pd-Based Amorphous Alloys with Wide Supercooled Liquid Region by Anomalous X-ray Scattering

1999 ◽  
Vol 40 (6) ◽  
pp. 491-497 ◽  
Author(s):  
Changyong Park ◽  
Masatoshi Saito ◽  
Yoshio Waseda ◽  
Nobuyuki Nishiyama ◽  
Akihisa Inoue
Keyword(s):  
Structural Study ◽  
Amorphous Alloys ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Influence of annealing on structural relaxation, crystallization, and deformation behavior of a Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass

2007 ◽  
Vol 22 (7) ◽  
pp. 1849-1858 ◽  
Author(s):  
Kwang Seok Lee ◽  
Jürgen Eckert ◽  
Hyun-Joon Jun ◽  
Young Won Chang
Keyword(s):  
Mechanical Properties ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Deformation Behavior ◽  
Structural Changes ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Compression Tests ◽  
X Ray

The influence of annealing on the structural changes and the mechanical properties of Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit-1) bulk metallic glass was systematically studied by varying the annealing times at 703 K. The evolution of the structural state at a relatively high temperature within the supercooled liquid region was studied by thermal analysis, x-ray diffraction, high-resolution transmission electron microscopy, extended x-ray absorption fine structure, and dilatometric measurements. The deformation behavior and the mechanical properties were also examined by carrying out hardness and compression tests for the specimens annealed for various times.

Formation of Ni57Zr20Ti22Pb1 Amorphous Powders by Mechanical Alloying

2007 ◽  
Vol 539-543 ◽  
pp. 2767-2772
Author(s):  
Pee Yew Lee ◽  
S.S. Hung ◽  
Jason S.C. Jang ◽  
Giin Shan Chen
Keyword(s):  
Thermal Stability ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Atomic Size ◽  
X Ray ◽  
Amorphous Powders ◽  
Thermal Stability Of

In the current study, the amorphization behavior of mechanically alloyed Ni57Zr20Ti22Pb1 powder was examined in details. The conventional X-ray diffraction results confirm that the fully amorphous powders formed after 5 hours of milling. The thermal stability of the Ni57Zr20Ti22Pb1 amorphous powders was investigated by differential scanning calorimeter (DSC). As the results demonstrated, the glass transition temperature (Tg) and the crystallization temperature (Tx) are 760 K and 850 K, respectively. The supercooled liquid region is 90 K. The appearance of wide supercooled liquid region may be mainly due to the Pb additions which cause the increasing differences in atomic size of mechanically alloyed Ni57Zr20Ti22Pb1 powders.

scholarly journals Glass formation in a (Ti, Zr, Hf)–(Cu, Ni, Ag)–Al high-order alloy system by mechanical alloying

2003 ◽  
Vol 18 (9) ◽  
pp. 2141-2149 ◽  
Author(s):  
L. C. Zhang ◽  
Z. Q. Shen ◽  
J. Xu
Keyword(s):  
Glass Transition ◽  
Mechanical Alloying ◽  
Glass Formation ◽  
Melt Spinning ◽  
Glassy Alloy ◽  
Alloy System ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
High Order ◽  
Liquid Region

In this work, glass formation under high-energy ball milling was investigated for a (Ti0.33Zr0.33Hf0.33)50(Ni0.33Cu0.33Ag0.33)40Al10 high-order alloy system with equiatomic substitution for early and late transition-metal contents. For comparison, an amorphous alloy ribbon with the same composition was prepared using the melt-spinning method as well. Structural features of the samples were characterized using x-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. Mechanical alloying resulted in a glassy alloy similar to that obtained by melt spinning. However, the glass formation was incomplete, and a small amount of unreacted crystallites smaller than 30 nm in size still remained in the final ball-milled product. Like the melt-spun glass, the ball-milled glassy alloy also exhibited a distinct glass transition and a wide supercooled liquid region of about 80 K. Crystallization of this high-order glassy alloy proceeded through two main stages. After the primary nanocrystallization was completed, the remaining amorphous phase also behaved as a glass, showing a detectable glass transition and a large supercooled liquid region of about 100 K.

GLASS FORMING ABILITY AND KINETIC CHARACTERS OF PARAMAGNETIC Nd60Co40-xAlx(x=5, 10, 15) BULK METALLIC GLASSES

2004 ◽  
Vol 18 (14) ◽  
pp. 679-685 ◽  
Author(s):  
L. XIA ◽  
Y. D. DONG
Keyword(s):  
Glass Transition ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Glass Forming Ability ◽  
Ternary Alloys ◽  
Liquid Region ◽  
Scanning Calorimetry ◽  
Glass Forming

Paramagnetic Nd 60 Co 40-x Al x(x=5, 10, 15) bulk metallic glasses (BMGs) were prepared in the shape of rods 2 mm in diameter by suction casting. The ternary alloys have shown distinct glass transitions in Differential Scanning Calorimetry (DSC) measurements and excellent glass-forming ability. The glass transition and crystallization behaviors as well as their kinetics have been studied. The reduced glass transition temperature and the supercooled liquid region of the alloys were found to increase with the increasing content of Al . The role of Al was discussed. The parameter γ defined by Liu et al. was employed to discuss the glass-forming ability of the alloys and the critical cooling rates as well as the critical section thickness of the alloys were predicted accordingly.

An anomalous X-ray structural study of an amorphous La55Al25Ni20 alloy with a wide supercooled liquid region

1992 ◽  
Vol 150 (1-3) ◽  
pp. 380-385 ◽  
Author(s):  
E. Matsubara ◽  
T. Tamura ◽  
Y. Waseda ◽  
T. Zhang ◽  
A. Inoue ◽  
...  
Keyword(s):  
Structural Study ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
X Ray
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