Thermomechanical characterization of Cu47.5Zr47.5Al5 bulk metallic glass within the homogeneous flow regime

Lee, Kwang Seok; Jun, Hyun Jo; Pauly, S.; Bartusch, Birgit; Chang, Young Won; Eckert, J.

doi:10.1016/j.intermet.2008.09.011

Cited by 22 publications

(8 citation statements)

References 40 publications

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“…To investigate whether Eq. (7) stands in other MG systems, we collect the available data of Q and m from literatures [56][57][58][59][60][61][62][63] for different MGs and estimate their E a (T g ) using Eq. (5).…”

Section: Correlation Between Glass Transition and Plastic Deformationmentioning

confidence: 99%

Correlation between relaxations and plastic deformation, and elastic model of flow in metallic glasses and glass-forming liquids

Wang¹

2011

Journal of Applied Physics

152

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We study the similarity and correlations between relaxations and plastic deformation in metallic glasses (MGs) and MG-forming liquids. It is shown that the microscope plastic events, the initiation and formation of shear bands, and the mechanical yield in MGs where the atomic sites are topologically unstable induced by applied stress, can be treated as the glass to supercooled liquid state transition induced by external shear stress. On the other hand, the glass transition, the primary and secondary relaxations, plastic deformation and yield can be attributed to the free volume increase induced flow, and the flow can be modeled as the activated hopping between the inherent states in the potential energy landscape. We then propose an extended elastic model to describe the flow based on the energy landscape theory. That is, the flow activation energy density is linear proportional to the instantaneous elastic moduli, and the activation energy density q E is determined to be a simple expression of q E ¼ 10 11 G þ 1 11 K. The model indicates that both shear and bulk moduli are critical parameters accounting for both the homogeneous and inhomogeneous flows in MGs and MG-forming liquids. The elastic model is experimentally certified. We show that the elastic perspectives offers a simple scenario for the flow in MGs and MG-forming liquids and are suggestive for understanding the glass transition, plastic deformation, and nature and characteristics of MGs V C

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Section: Correlation Between Glass Transition and Plastic Deformationmentioning

confidence: 99%

Correlation between relaxations and plastic deformation, and elastic model of flow in metallic glasses and glass-forming liquids

Wang¹

2011

Journal of Applied Physics

152

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“…Once the temperature drops from 1215°C, the CuZr primary dendrites start to grow form nuclei and the presence of excess solute (Al) substitutes the Cu atoms in equiatomic CuZr primary dendritic phase since the difference in atomic radii between the Al and the Cu atoms is less when compared with Al and Zr, and the second reason is high negative enthalpy of mixing between Al and Zr when compared to the Al and Cu. The rejected Cu atoms from the solidification front increase the Cu content in the remaining liquid (composition of liquid, shifted toward the left side from the equiatomic) and forms eutectic compound (alternate layer of Cu 10 Zr 7 and CuZr 2 at room temperature) as per the phase diagram ( Ref 22,23). Since the cooling rate is very high in the copper mold, one can expect a high temperature eutectic structure (alternate layer of Cu 10 Zr 7 and CuZr) to be retained at room temperature.…”

Section: (B) For 260 A)mentioning

confidence: 99%

“…All the specimens show a distinct glass transition (T g ) at about 705 K and a sharp crystallization peak (T x ) at 760 K as shown inTable 1(Ref16,20,21,23,24). The enthalpy of crystallization (D cryst H m ) is very sensitive to the amount of the crystalline phase present in the sample.…”

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confidence: 96%

Influence of Superheat on Microstructure and Mechanical Properties of Ductile Cu47.5Zr47.5Al5 Bulk Metallic Glass-Matrix Composite

Antonysamy

Pauly

Dhindaw

et al. 2010

J. of Materi Eng and Perform

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Generally bulk metallic glasses (BMGs) posses very less ductility and toughness at room temperature. Over the recent past years to improve up on these properties in many alloy system BMG composites have been developed. It was also reported that Cu 47.5 Zr 47.5 Al 5 BMG composite shows a very high strength together with an extensive work hardening-like behavior of large ductility around 18%. In this study, the influence of superheat on microstructure and the resulting mechanical properties in Cu 47.5 Zr 47.5 Al 5 bulk metallic glass-matrix composite alloy has been studied. The Cu 47.5 Zr 47.5 Al 5 melt solidifies into a composite microstructure consisting of crystalline precipitates embedded in an amorphous matrix. The crystalline phase consists of B2 CuZr (cubic primitive with CsCl structure) with a small amount of monoclinic CuZr martensitic structure embedded in an amorphous matrix. The volume fraction of crystalline phases varies with melting current as well as position along the length of the as-cast rod, depending on the local cooling condition. The volume fraction and the distribution of the crystalline precipitates are heterogeneous in the amorphous matrix. Room temperature uniaxial compression tests revealed high yield strength ranging from 796 to 1900 MPa depending upon the volume fraction of the crystalline phases present. The presence of the dendritic B2 CuZr significantly improved the ductility. The BMG composites show a pronounced plastic strain up to 14% for the higher volume fraction of crystalline phase.

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“…V act ¼150-200 Ǻ 3 for Zr 52. 5 [21]. Providing the average atomic volume of the alloy is about 10.636 Ǻ 3 , a unit local flow event at least includes 27-29 atoms for the BMGCs during the high-temperature deformation.…”

Section: Viscosity Flow Behavior Of All the Bmgcsmentioning

confidence: 99%

Homogeneous viscous flow behavior of a Cu–Zr based bulk metallic glass composites

Zhang

Yuan

Feng

et al. 2015

Materials Science and Engineering: A

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Thermomechanical characterization of Cu47.5Zr47.5Al5 bulk metallic glass within the homogeneous flow regime

Cited by 22 publications

References 40 publications

Correlation between relaxations and plastic deformation, and elastic model of flow in metallic glasses and glass-forming liquids

Correlation between relaxations and plastic deformation, and elastic model of flow in metallic glasses and glass-forming liquids

Influence of Superheat on Microstructure and Mechanical Properties of Ductile Cu47.5Zr47.5Al5 Bulk Metallic Glass-Matrix Composite

Homogeneous viscous flow behavior of a Cu–Zr based bulk metallic glass composites

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