Temperature-Time-Transformation Curve and Viscous Flow Deformation of Zr&lt;SUB&gt;55&lt;/SUB&gt;Cu&lt;SUB&gt;30&lt;/SUB&gt;Al&lt;SUB&gt;10&lt;/SUB&gt;Ni&lt;SUB&gt;5&lt;/SUB&gt; Bulk Glassy Alloy

Zhu, Shengli; Wang, Xinmin; Qin, Fengxiang; Abe, Kenta; Kimura, Hisamichi; Inoue, Akihisa

doi:10.2320/matertrans.47.2308

Cited by 6 publications

(3 citation statements)

References 21 publications

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“…The TTT diagrams summarized in Table 1 were determined from samples that were cooled from a temperature above T l down to the isothermal temperature. TTT diagrams have also been obtained by heating the BMG former from ambient temperature up to the isothermal temperature 18, 89, 97–99. At low temperatures (see Fig.…”

Section: Crystallizationmentioning

confidence: 99%

Processing of Bulk Metallic Glass

2010

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Bulk metallic glass (BMG) formers are multicomponent alloys that vitrify with remarkable ease during solidification. Technological interest in these materials has been generated by their unique properties, which often surpass those of conventional structural materials. The metastable nature of BMGs, however, has imposed a barrier to broad commercial adoption, particularly where the processing requirements of these alloys conflict with conventional metal processing methods. Research on the crystallization of BMG formers has uncovered novel thermoplastic forming (TPF)-based processing opportunities. Unique among metal processing methods, TPF utilizes the dramatic softening exhibited by a BMG as it approaches its glass-transition temperature and decouples the rapid cooling required to form a glass from the forming step. This article reviews crystallization processes in BMG former and summarizes and compares TPF-based processing methods. Finally, an assessment of scientific and technological advancements required for broader commercial utilization of BMGs will be made.

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Section: Crystallizationmentioning

confidence: 99%

Processing of Bulk Metallic Glass

2010

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“…The crystallization at high temperatures was confirmed by XRD. Bigger relative displacements can be obtained when the temperature is in the range from 713 to 733 K. 17) The effect of the viscous flow deformation under various temperatures on the T g , ÁT x , ÁH=ÁH as-cast and hardness had been discussed in our previous work. 18) With increasing deformation temperature, T g increases and the endothermic glass transition event becomes weak.…”

Section: Effect Of Temperature On Viscous Flow Behaviormentioning

confidence: 99%

“…Higher strain rate can reduce the fabrication time at high temperature, therefore, reduces the possibility of crystallization. XRD results show the absence of crystallization for the sample compressed at 723 K. 17) Figure 4 shows the effect of the strain rate on the T g , ÁT x , ÁH=ÁH as-cast and hardness. The compression temperature, time and initial stress are 723 K, 100 s and 160 MPa, respectively.…”

Section: Effect Of Strain Rate On Viscous Flow Behaviorsmentioning

confidence: 99%

The Influence of Viscous Flow Deformation on the Thermal Stability and Hardness of ZrCuAlNi Bulk Glassy Alloy

et al. 2007

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We investigated the thermal stability and hardness of a Zr 55 Cu 30 Al 10 Ni 5 bulk glassy alloy after isothermal viscous flow deformation in the supercooled liquid region. The influence of deformation temperature, holding time and initial strain rate on the thermal stability and hardness of a Zr 55 Cu 30 Al 10 Ni 5 bulk glassy alloy subjected to the high temperature compression test was examined by differential scanning calorimetry (DSC) and with a Vickers micro-hardness tester. The results showed that the incubation time for isothermal annealing crystallization reduced during the viscous flow deformation. Thermal stability of supercooled liquid decreased after viscous flow deformation. As the deformation temperature increased, the SCL region decreases. At lower temperatures below 713 K the structural relaxation occurred, resulting in a slight increase in hardness. The crystallization at higher temperatures of over 723 K caused a rapid increase in hardness. The supercooled liquid region decreased and the hardness increased with increasing deformation time. Higher strain rate resulted in larger deformation in the same deformation time, and had slight influence on the thermal stability and hardness of the Zr 55 Cu 30 Al 10 Ni 5 glassy alloy. When the Zr 55 Cu 30 Al 10 Ni 5 bulk glassy alloy was compressed for 300 s with an initial strain rate of 3:3 Â 10 À3 s À1 at the temperatures of 723 K, nanocrystallization occurred, and the grain size was evaluated to be smaller than 5 nm.

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High-Temperature Deformation Behavior and Formability of a Zr-Cu-Al-Ni Bulk Metallic Glass

Jun

Lee

Eckert

et al. 2007

Metall Mater Trans A

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The deformation behavior of a monolithic Zr 55 Cu 30 Al 10 Ni 5 (at. pct) bulk metallic glass (BMG) fabricated by suction casting has been investigated at elevated temperatures in this study. A series of compression tests has been performed in the supercooled liquid temperature region. In the homogeneous flow regime, this alloy exhibited a transition from the Newtonian to nonNewtonian flow depending upon both the strain rate and the temperature. These two flow modes were then described by applying the Newtonian viscous flow theory and the transition state theory, respectively. On the basis of a dynamic materials model (DMM), a processing map could successfully be constructed to estimate the feasible forming conditions for this BMG alloy. Imaginary laboratory-scale extrusion tests were also performed to determine solid-tosolid formability, and the results from both the finite element method (FEM)-based simulation and processing map were then compared and discussed.

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Temperature-Time-Transformation Curve and Viscous Flow Deformation of Zr<SUB>55</SUB>Cu<SUB>30</SUB>Al<SUB>10</SUB>Ni<SUB>5</SUB> Bulk Glassy Alloy

Cited by 6 publications

References 21 publications

Processing of Bulk Metallic Glass

Processing of Bulk Metallic Glass

The Influence of Viscous Flow Deformation on the Thermal Stability and Hardness of ZrCuAlNi Bulk Glassy Alloy

High-Temperature Deformation Behavior and Formability of a Zr-Cu-Al-Ni Bulk Metallic Glass

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