Air Oxidation Kinetics Study of Zr58Nb3Cu16Ni13Al10 Bulk Metallic Glass

2009 ◽  
Vol 283-286 ◽  
pp. 209-213 ◽  
Author(s):  
Dong Ya Huang ◽  
Xiang Jin Zhao ◽  
Tao Zhang ◽  
Vincent Ji

The isothermal oxidation behavior of Zr58Nb3Cu16Ni13Al10 bulk metallic glass (BMG) under dry air in the glassy state and the supercooled liquid state (SLS) was studied by the thermogravimetric method. The oxidation rate and thickness growth speed in the SLS were both hugely higher than in the glassy state. The oxidation kinetics of BMG in both states for 1.5 hours was different, the parabolic law was followed in the glassy state at 300°C and 350°C, contrarily the linear law was followed in SLS at 400 °C. After the oxidation for 126 hours in SLS, the oxidation kinetics possessed two stages, the linear stage and the parabolic stage. The diffusion of the Cu2+ ion and CuZr intermetallic alloys were detected by GIXRD.

2011 ◽  
Vol 675-677 ◽  
pp. 209-212 ◽  
Author(s):  
Dong Ya Huang ◽  
Bin Wang ◽  
Vincent Ji ◽  
Tao Zhang

The isothermal initial oxidation kinetics of Zr55Cu30Al10Ni5 bulk metallic glass in glassy state (lower than Tg = 685K) and in surpercooled liquid state (Tg = 685 K < T < Tx=774 K) is investigated under dry air by thermogravimetric method in short-term stage (for 1.5 hours). A protective parabolic law is followed in glassy state, except at 573 K where a linear law is followed. The self-limiting oxidation kinetics evolves from a short linear stage to a steady mild growth stage in supercooled liquid state at 723 K, which is induced mainly by crystallization and by the fast growth of dense scale. The growth of the scale is dominated by the formation of tetragonal-ZrO2 (t- ZrO2) in the range of 623 K - 673 K in glassy state for 1.5 hours. The activation energy of oxidation is mainly piloted by the diffusion of oxygen ions.


2006 ◽  
Vol 20 (05) ◽  
pp. 225-232 ◽  
Author(s):  
L. XIA ◽  
Y. D. DONG

In this work, we studied the thermal stability and kinetics of Nd 55 Al 20 Fe 25 bulk metallic glass (BMG) with distinct glass transition and multistage crystallizations. The kinetics of glass transition and crystallizations were investigated using the Kissinger method and the ideal glass transition temperature of the alloy was obtained via Lasoka's equation. The thermal stability of the BMG was investigated by means of continuous transformation diagrams obtained from the extension of Kissinger analysis. It is suggested that the stability limit of the supercooled liquid, i.e. Kauzmann temperature, could also be regarded as the long-term stability criteria of the BMG.


2007 ◽  
Vol 539-543 ◽  
pp. 2117-2122 ◽  
Author(s):  
H.H. Hsieh ◽  
W. Kai ◽  
C.Y. Lin ◽  
Tsung Shune Chin

The oxidation behavior of Y56Al24Co20 bulk metallic glass containing ~4.2% Y-rich particles was studied over the temperature range of 325-450oC in dry air. The results showed that the oxidation kinetics of the alloy followed the parabolic rate law at T≤375oC, with rate constants generally increased with temperature. Conversely, para-linear kinetics were observed at higher temperatures (T≥400oC). The scales formed on the Y-base amorphous composite were temperature dependent, consisting of exclusively yttrium oxides (Y2O3) at T≤375oC and of mostly Y2O3 and alumina (Al2O3) at temperatures. No evidence of any cobalt-containing oxide was found in the scale.


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).


2006 ◽  
Vol 8 (8) ◽  
pp. 714-719 ◽  
Author(s):  
D. Qiao ◽  
C. Fan ◽  
P. K. Liaw ◽  
H. Choo

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