Deformation Behavior in La55Al25Ni20 Metallic Glass

1998 ◽  
Vol 554 ◽  
Author(s):  
Y. Kawamura ◽  
T. Nakamura ◽  
A. Inoue
Keyword(s):  
Metallic Glass ◽  
Deformation Behavior ◽  
Tensile Deformation ◽  
Supercooled Liquid ◽  
Glass Ribbon ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Newtonian Viscosity ◽  
Metallic Glass Ribbon ◽  
Elongation To Failure

AbstractWe investigated the deformation behavior of the supercooled liquid in a La55Al25Ni20 (at.%) metallic glass ribbon that has a wide supercooled liquid region of 65 K before crystallization. The deformation of the metallic glass was divided into three types, namely, homogeneous deformations with and without a stress overshoot and an inhomogeneous deformation. The supercooled liquid above the glass transition temperature (Tg) exhibited a Newtonian viscosity and superplastic-like behavior during isothermal tensile deformation. The metallic glass was elongated as much as 1000 % at high strain rates ranging from 10−2 s−1 to 10o s−1 without embrittlement. The maximum elongation to failure was in excess of 1800 % at a strain rate of 1.7×10−1 s−1 and at 503 K (Tg+20 K, 0.71Tm) under about 40 MPa.

Deformation Behavior of Ti–Zr–Ni–Cu–Be Metallic Glass and Composite in the Supercooled Liquid Region

2004 ◽  
Vol 19 (3) ◽  
pp. 937-942 ◽  
Author(s):  
D.H. Bae ◽  
J.M. Park ◽  
J.H. Na ◽  
D.H. Kim ◽  
Y.C. Kim ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Deformation Behavior ◽  
Crystallization Behavior ◽  
Flow Behavior ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Β Phase ◽  
Metallic Glass Matrix Composite ◽  
Elongation To Failure

The deformation behavior of Ti-based bulk metallic glass (BMG) and metallic glass matrix composite (MGMC), both having a multistep crystallization behavior upon heating, has been investigated in the supercooled liquid region. The BMG deforms homogeneously and exhibits moderate elongation to failure due to its multistep crystallization behavior, but shows a significant variation of the flow stress during deformation. For the MGMC containing an in situ β-phase, a stress-overshoot characteristic, observed in the BMG, is not presented, but elongation to failure is rather limited because the crystalline β-phase prevents the viscous flow of the amorphous phase. The different presence of the crystalline phases in the metallic glasses can differently affect the flow behavior of metallic glass in the supercooled liquid region.

Flow Stress and Elongation of Superplastic Deformation in La55Al25Ni20 Metallic Glass

1999 ◽  
Vol 601 ◽  
Author(s):  
Y. Kawamura ◽  
A. Inoue
Keyword(s):  
Flow Stress ◽  
Metallic Glass ◽  
Strain Rate ◽  
Superplastic Deformation ◽  
Constant Strain Rate ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Elongation To Failure ◽  
Crosshead Velocity

AbstractWe have investigated the flow stress and elongation of superplastic deformation in a La55Al25Ni20 (at%) metallic glass that has a wide supercooled liquid region of 72 K before crystallization. The superplasticity that appeared in the supercooled liquid region was generated by the Newtonian viscous flow that exhibits the m value of unity. The elongation to failure was restricted by the transition of the Newtonian flow to non-Newtonian one and the crystallization during deformation. We succeeded in establishing the constitutive formulation of the flow stress in the supercooled liquid region. Its formulation was expressed very well by a stretched exponential function σflow=Dε exp(H*/RT) [1-exp(E/{ε exp(H**/RT)}0.82)]. Formulations describing the elongation to failure in constant-strain-rate and constant-crosshead velocity tests were, moreover, established. It was found from the simulation that the maximum elongation in the constant-strain-rate test reached more than 106% which was two orders of magnitude larger than that in the constant-crosshead-velocity test.

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.

Deformation behavior of a TiZr-based metallic glass composite containing dendrites in the supercooled liquid region

2020 ◽  
Vol 37 ◽  
pp. 64-70 ◽  
Author(s):  
Wu Longjun ◽  
Zhu Zhengwang ◽  
Liu Dingming ◽  
Fu Huameng ◽  
Li Hong ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Deformation Behavior ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Glass Composite
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