Superplastic Deformation and Thermal Crystallization Behavior of Supercooled Liquid in Zr-Ni Based Metallic Glass

2006 ◽  
Vol 512 ◽  
pp. 37-40 ◽  
Author(s):  
Takeshi Nagase ◽  
Mitsuo Nakamura ◽  
Yukichi Umakoshi
Keyword(s):  
Metallic Glass ◽  
Strain Rate ◽  
Strain Hardening ◽  
Crystallization Behavior ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Viscous Deformation ◽  
Thermal Crystallization ◽  
Strain Behavior

Superplastic viscous deformation and thermal crystallization behavior of supercooled liquid in Zr60.0Al15.0Ni25.0 metallic glass were investigated. The temperature interval of the supercooled liquid region (∆Tx) was 83 K. The supercooled liquid showed significant viscous plasticity, resulting in large elongation and high strain rate deformation. The stress-strain behavior can be classified into three types: stress overshoot, stable viscous flow with constant flow stress and strain hardening. The strain hardening is due to the precipitation of Zr6Al2Ni crystalline phase with ellipsoidal morphology. Superplastic viscous deformation behavior is very sensitive to thermal crystallization as well as to deformation temperature and strain rate.

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.

Crystallization behavior of ZrAlNiCu bulk metallic glass with wide supercooled liquid region

2003 ◽  
Vol 57 (13-14) ◽  
pp. 1894-1898 ◽  
Author(s):  
Yu-Lai Gao ◽  
Jun Shen ◽  
Jian-Fei Sun ◽  
Gang Wang ◽  
Da-Wei Xing ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Crystallization Behavior ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region

High Temperature Deformation in the Amorphous or Partially Crystallized Zr41.2Ti13.8Cu12.5Ni10Be22.5 Bulk Metallic Glass

2002 ◽  
Vol 754 ◽  
Author(s):  
Q. Wang ◽  
J.J. Blandin ◽  
M. Suery ◽  
J.M. Pelletier
Keyword(s):  
High Temperature ◽  
Metallic Glass ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Liquid Region ◽  
Newtonian Behavior

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.

Crystallization during Superplastic Deformation in a Zr65Al10Ni10Cu15 Glass Metallic Alloy

2005 ◽  
Vol 475-479 ◽  
pp. 2981-2986
Author(s):  
Woo Jin Kim ◽  
H.S. Kim ◽  
Ha Guk Jeong
Keyword(s):  
Strain Rate ◽  
Strain Hardening ◽  
Superplastic Deformation ◽  
Large Strain ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Metallic Alloy ◽  
Liquid Region ◽  
Superplastic Behavior ◽  
Stress Strain

Superplastic behavior of the Zr65Al10Ni10Cu15 glass metallic alloy produced by powdermetallurgy method was examined in the supercooled liquid region. Stress-strain and stress-strain rate relationships showed that Newtonian viscous flow governed the plastic flow until strain hardening took place. The large strain hardening was proved to a result of occurrence of crystallization during deformation.

Homogeneous Flow of In Situ Bulk Metallic Glass Matrix Composite

2007 ◽  
Vol 551-552 ◽  
pp. 561-567
Author(s):  
K.C. Chan ◽  
Q. Chen ◽  
L. Liu
Keyword(s):  
Metallic Glass ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Free Volume Theory ◽  
Glass Matrix Composite ◽  
Metallic Glass Matrix Composite

The compressive deformation behavior of as-cast Zr55.9Cu18.6Ta8Al7.5Ni10 Bulk Metallic Glass (BMG) composite with micro-scale particles of Ta-rich solid solution embedded in an amorphous matrix was investigated in the supercooled liquid region. It was found that the apparent viscosity of the BMG is dependent on temperature and strain rate. A deviation from a Newtonian behavior was observed at high strain rate and low temperature. The experimental results can be described by a master curve based on a stretched exponential function and the free volume theory. The structural state and the thermal ability of the BMG composite after deformation are also discussed in the paper.

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.

scholarly journals Effects of Annealing on Enthalpy Recovery and Nanomechanical Behaviors of a La-Based Bulk Metallic Glass

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 579
Author(s):  
Ting Shi ◽  
Lanping Huang ◽  
Song Li
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Structural Relaxation ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
Nanoindentation Measurement

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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