Thermal stabilities of some glassy metals with a wide supercooled liquid region

1997 ◽  
Vol 226-228 ◽  
pp. 209-212 ◽  
Author(s):  
O. Haruyama ◽  
H.M. Kimura ◽  
A. Inoue
2013 ◽  
Vol 791-793 ◽  
pp. 435-439 ◽  
Author(s):  
Zhong Yuan Suo ◽  
Jian Jun Chen ◽  
Yan Ling Song ◽  
Ke Qiang Qiu

A new Ti-based amorphous alloy Ti35Zr21Cu40Si4 with about 80 μm thickness and 5~8 mm width was fabricated by melt spinning method. The phase structure and thermal stabilities of the Ti35Zr21Cu40Si4 amorphous alloy were investigated by the X-ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. The Ti35Zr21Cu40Si4 amorphous alloy was cultivated in the simulate body fluid (SBF) for 15 days. And the blood compatibility was evaluated by dynamic clotting time and hemolysis rate test. The Ti35Zr21Cu40Si4 alloy exhibits fully amorphous phase and high thermal stability with a supercooled liquid region (ΔTx) of 80K. The Ca phosphates depositions on alloy surfaces were gained after 15 days. Moreover, n (Ca)/n (P) atom ratio of the deposition is about 1.65/1, which approaches to that of human bone 1.66/1, suggesting that the Ti35Zr21Cu40Si4 amorphous alloy is with an excellent biocompatibility. The Ti35Zr21Cu40Si4 amorphous ribbon has lower hemolysis ratio of 0.562%, which can reduce wrecking degree of erythrocytes, compared with medical standards of the hemolysis rate (less than 5%). These are favorable for application to biomaterials.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 929
Author(s):  
Dandan Liang ◽  
Jo-Chi Tseng ◽  
Xiaodi Liu ◽  
Yuanfei Cai ◽  
Gang Xu ◽  
...  

This study investigated the structural heterogeneity, mechanical property, electrochemical behavior, and passive film characteristics of Fe–Cr–Mo–W–C–B–Y metallic glasses (MGs), which were modified through annealing at different temperatures. Results showed that annealing MGs below the glass transition temperature enhanced corrosion resistance in HCl solution owing to a highly protective passive film formed, originating from the decreased free volume and the shrinkage of the first coordination shell, which was found by pair distribution function analysis. In contrast, the enlarged first coordination shell and nanoscale crystal-like clusters were identified for MGs annealed in the supercooled liquid region, which led to a destabilized passive film and thereby deteriorated corrosion resistance. This finding reveals the crucial role of structural heterogeneity in tuning the corrosion performance of MGs.


Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 579
Author(s):  
Ting Shi ◽  
Lanping Huang ◽  
Song Li

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).


2003 ◽  
Vol 18 (9) ◽  
pp. 2115-2121 ◽  
Author(s):  
Baolong Shen ◽  
Akihisa Inoue

Glassy Fe65Co10Ga5P12C4B4 alloy powders with a large supercooled liquid region of 50 K before crystallization were synthesized in the particle size range below 125 μm by Ar gas atomization. With the aim of developing a large-size Fe-based glassy core with good soft magnetic properties, the consolidation method of spark plasma sintering was applied to the Fe65Co10Ga5P12C4B4 glassy powders. The existence of the supercooled liquid region enabled us to form a large-size glassy alloy disc 20 mm in diameter and 5 mm in thickness with a high relative density of 99.7% at the glass-transition temperature of 723 K and under the external applied pressure of 300 MPa. The resulting glassy core of 18 mm in outer diameter, 10 mm in inner diameter, and 4 mm in thickness exhibits good soft magnetic properties: 1.20 T for saturation magnetization, 6 A/m for coercive force, and 8900 for maximum permeability. The good soft magnetic properties of the Fe-based bulk glassy core are attributed to the combination of the high relative density and the maintenance of the single glassy structure.


2004 ◽  
Vol 449-452 ◽  
pp. 941-944
Author(s):  
W.B. Kim ◽  
B.J. Ye ◽  
S. Yi

The effects of partial replacements of Zr by Y in the alloy Ni60Zr25-xAl8Yx(x=0 and 7 at %) on the crystallization behaviors of amorphous alloys were studied using isothermally heattreated ribbons. With the partial replacement, the supercooled liquid region upon continuous heating was significantly extended indicating that crystallization can be effectively suppressed by the optimum amount of Zr replacement by Y. The first phase appeared during crystallization was identified as the ternary compound AlNi2Zr while the single exothermic event could be observed upon heating the amorphous ribbons. The AlNi2Zr phase was decomposed into binary compounds upon further heating. Therefore, the extended supercooled liquid region of the alloy Ni60Zr25Al8Y7was attributed to the suppression of AlNi2Zr phase formation by the partial replacement of Zr by Y. The effects of Y on the crystallization behaviors were discussed on the basis of atomic configuration of the supercooled liquid.


2002 ◽  
Vol 17 (7) ◽  
pp. 1743-1749 ◽  
Author(s):  
L. C. Zhang ◽  
J. Xu ◽  
E. Ma

A high-energy ball milling procedure has been developed to produce amorphous alloys in Ti50(Cu0.45Ni0.55)44−xAlxSi4B2 (x= 0, 4, 8, 12) powder mixtures. The milling products were characterized using x-ray diffraction, differential scanning calorimetry, and transmission electron microscopy. The Ti-based amorphous alloy powders prepared through this solid-state process exhibit a well-defined glass transition and a supercooled liquid region (ΔTx =64 K) close to the largest achieved so far for Ti-based undercooled melts. The substitution of Al for Cu and Ni has beneficial effects on stabilizing the supercooled liquid. Residual nanocrystals of the αTi structure are uniformly dispersed in the amorphous matrix. The composite alloy powders offer the potential for consolidation in the supercooled liquid region to bulk lightweight amorphous alloys and the possibility to attain desirable mechanical properties.


Sign in / Sign up

Export Citation Format

Share Document