High Temperature Deformation Characteristics of Zr76.11Ti4.20Cu4.51Ni3.16Be1.49Nb10.53 Bulk Metallic Glass Composite

2007 ◽  
Vol 539-543 ◽  
pp. 2111-2116 ◽  
Author(s):  
H.J. Jun ◽  
Kwang Seok Lee ◽  
Yeon Chul Yoo ◽  
Young Won Chang

The thermal properties of a Zr76.11Ti4.20Cu4.51Ni3.16Be1.49Nb10.53 bulk metallic glass (BMG) have been investigated by using a differential scanning calorimeter (DSC). The composition of dendrite phase was then subsequently analyzed by using an EPMA, XRD, and TEM. The glass transition and crystallization onset temperatures were determined as 339.7 °C and 375.8 °C for this BMG, respectively. The Zr-Ti-Nb dendrite phase was found to have a BCC structure. Mechanical properties have also been examined by conducting a series of uniaxial compression tests at various temperatures within supercooled liquid region under the strain rates between 10-4 /s and 3×10-2 /s. The hardness of matrix and dendrite was then measured separately. The glassy matrix appears to play major role on the elongation, while dendrite phase on the strength of this BMG composite at high temperatures within supercooled liquid region.

2002 ◽  
Vol 754 ◽  
Author(s):  
Q. Wang ◽  
J.J. Blandin ◽  
M. Suery ◽  
J.M. Pelletier

ABSTRACTThe high temperature deformation of the Zr41.2Ti12.5Cu13.8Ni10Be22.5 bulk metallic glass (BMG) is studied in the supercooled liquid region. Both fully amorphous and partially crystallized states are investigated. In the studied experimental domain, the amorphous alloy exhibits a Newtonian behavior at high temperature and/or low strain rate whereas a transition to non-Newtonian behavior is observed when the temperature is decreased and/or the strain rate is increased. In the Newtonian domain, the dependency of the viscosity upon temperature can be described by an Arrhénius law. As far as the as-received alloy is maintained at high temperature for which phase separation and primary crystallisation is expected, the flow stress continuously increases, which is at least partly attributed to a change in the residual amorphous phase.


2007 ◽  
Vol 22 (7) ◽  
pp. 1849-1858 ◽  
Author(s):  
Kwang Seok Lee ◽  
Jürgen Eckert ◽  
Hyun-Joon Jun ◽  
Young Won Chang

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.


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).


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