scholarly journals Glass-forming ability and crystallization behavior of Co62−xFexNb6Zr2B30 (x=0,16) amorphous alloys with large supercooled liquid region

2002 ◽  
Vol 92 (11) ◽  
pp. 6607-6611 ◽  
Author(s):  
J. M. Borrego ◽  
C. F. Conde ◽  
A. Conde ◽  
S. Roth ◽  
H. Grahl ◽  
...  
Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 383 ◽  
Author(s):  
Xuan Liu ◽  
Xingfu Wang ◽  
Yongli Si ◽  
Xiaokang Zhong ◽  
Fusheng Han

In this study, the formation and crystallization of the Al70Fe12.5V12.5Nb5 amorphous alloys has been investigated. The addition of Nb enhances the supercooled liquid region and glass forming ability of the Al-Fe-V amorphous alloys. The Al70Fe12.5V12.5Nb5 amorphous alloy exhibits two distinct crystallization steps and a large supercooled liquid region at more than 100 K. Kissinger and Ozawa analyses showed that the two activation energies for crystallization (Ex) were estimated to be 366.3 ± 23.9 and 380.5 ± 23.9 kJ/mol. Large supercooled liquid regions are expected to gain an application field of Al-based amorphous alloys.


Open Physics ◽  
2004 ◽  
Vol 2 (1) ◽  
Author(s):  
M. Shapaan ◽  
J. Lábár ◽  
L. Varga ◽  
J. Lendvai

AbstractGlass-forming ability (GFA) and thermal stability of Fe62Nb8B30, Fe62Nb6Zr2B30 and Fe72Zr8B20 at % amorphous alloys were investigated by calorimetric (DSC and DTA) measurements. The crystallization kinetics was studied by DSC in the mode of continuous versus linear heating and it was found that both the glass transition temperature, Tg, and the crystallization peak temperature, Tp, display strong dependence on the heating rate. The partial replacement of Nb by Zr leads to lower Tg and Tx temperatures and causes a decrease of the supercooled liquid region. JMA analysis of isothermal transformation data measured between Tg and Tx suggests that the crystallization of the Fe62Nb8B30 and Fe62Nb6Zr2B30 amorphous alloys take place by three-dimensional growth with constant nucleation rate. Nb enhances the precipitation of the metastable Fe23B6 phase and stabilizes it up to the third crystallization stage. Zr addition increases the lattice constant of Fe23B6 and, at the same time, decreases the grain size.


2016 ◽  
Vol 254 ◽  
pp. 60-64 ◽  
Author(s):  
Parthiban Ramasamy ◽  
Mihai Stoica ◽  
Mariana Calin ◽  
Jurgen Eckert

[(Fe0.5Co0.5)0.75B0.2Si0.05]96Nb4}100-x,y(Gdx, Cuy) (x = 0.5, 1 and 2), (y = 0.5) alloys with different diameters were prepared by copper mold casting. The structure, the thermal and the magnetic properties were studied by X-ray diffraction, differential scanning calorimetry and vibrating sample magnetometry, respectively. Minor Cu addition completely changes the crystallization behavior, and also the glass-forming ability decreases because of the decrease in the supercooled liquid region. However, the magnetic properties are significantly improved upon annealing because of the precipitation of (Fe,Co) phase. In case of [(Fe0.5Co0.5)0.75B0.2Si0.05]96Nb4}100-x (Gdx) glass, Gd addition does not change the crystallization behavior. In turn, it increases the supercooled liquid region when compared with [(Fe0.5Co0.5)0.75B0.2Si0.05]96Nb4, but even then the glass-forming ability is reduced (critical glassy diameter dc < 1.5 mm). The saturation magnetization of the glass is also decreased with increasing Gd content.


2014 ◽  
Vol 790-791 ◽  
pp. 509-514 ◽  
Author(s):  
Kinga Tomolya ◽  
Dóra Janovszky ◽  
Anna Sycheva

The effect of nickel addition was studied in the CuZr system creating alloys with near eutectic composition. Nickel and aluminum have been regarded as useful elements to improve the plasticity, thermal stability of the CuZr-based amorphous alloys. Cu49Zr45Al6and (Cu49Zr45Al6)95Ni5were selected because of the good glass-forming ability. After 15 h of milling the structure of the powders was amorphous based on the XRD analysis. By adding nickel, the crystallization temperature (Tx) shifted to higher temperatures compared to CuZrAl alloy. The value of supercooled liquid region was 64 K, which means CuZrAl has a comparatively high glass forming ability.


2004 ◽  
Vol 19 (2) ◽  
pp. 427-428 ◽  
Author(s):  
Z.P. Lu ◽  
C.T. Liu

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.


2010 ◽  
Vol 504 ◽  
pp. S132-S134 ◽  
Author(s):  
Qikui Man ◽  
Huaijun Sun ◽  
Yaqiang Dong ◽  
Baolong Shen ◽  
Hisamichi Kimura ◽  
...  

2004 ◽  
Vol 18 (14) ◽  
pp. 679-685 ◽  
Author(s):  
L. XIA ◽  
Y. D. DONG

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.


2014 ◽  
Vol 670-671 ◽  
pp. 86-89
Author(s):  
Shi Wen He

A new bulk amorphous alloy, Y36Nd20Al24Co20, with a diameter of 5 mm was successfully fabricated by the method of equiatomic substitution for the Y element in Y56Al24Co20amorphous alloy. The values of the supercooled liquid region ∆Tx(=Tx-Tg), the reduced glass transition temperature Trg(=Tg/Tl) and the parameter γ (=Tx/(Tg+Tl)) for Y36Nd20Al24Co20bulk amorphous alloy are 60K, 0.605 and 0.415, respectively. The critical cooling rate of the Y36Nd20Al24Co20bulk amorphous alloy was determined to be 40 K/s, providing an indication that this alloy has a high glass-forming ability.


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