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hslining

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专业: 金属材料的制备科学与跨学

[交流] 最新非晶文献汇总－－5

4 Materials Science and Engineering: A - Article in Press, Accepted Manuscript

Strain rate response of mechanical behaviors for a Zr-based bulk metallic glass matrix composite

J.W. Qiaoa, Y. Zhanga, P. Fengb, Q.M. Zhangb and G.L. Chena

aState Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China
bState Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China

Received 10 December 2008; revised 19 February 2009; accepted 20 February 2009. Available online 9 March 2009.

Abstract
The strain rate response of compressive mechanical behaviors for a Zr60.0Ti14.7Nb5.3Cu5.6Ni4.4Be10.0 bulk metallic glass matrix composite with the tensile fracture strain of 2.9 %, was investigated. The dislocation-related deformation mode was employed to interpret the failure of the composite containing continuous network dendrites with high volume fraction. Under the quasi-static compression, a positive dependence of the plasticity on the increasing strain rate was obtained. However, upon the dynamic loading, the composite exhibited premature fracture and the very limited plasticity accompanied, which suggested the strain was not kinetically accommodated during the prompt deformation.

Keywords: Bulk metallic glass; Composite; Mechanical property; Dynamic compression; Strain rate response

2 Materials Science and Engineering: A - Article in Press, Accepted Manuscript

Dynamic viscoelasticity of Zr-Al-Ni-Cu metallic glass in the glass transition region
Y. Uenoa, M. Hojob, H. Numakuraa, T. Ichitsubob and J. Saidac

aDepartment of Materials Science, Osaka Prefecture University, Naka-ku, Sakai 599-8531, Japan
bDepartment of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
cCenter for Interdisciplinary Research, Tohoku University, Sendai 980-8578, Japan

Received 20 September 2008; accepted 4 October 2008. Available online 9 March 2009.

Abstract
Viscoelastic behaviour of a metallic glass Zr55Al10Ni5Cu30 has been studied by measuring the dynamic shear modulus G under forced vibration at low frequencies below 1 Hz. In measurements with increasing temperature, the shear modulus falls markedly at temperatures around the glass transition but at different rates under different vibration frequencies. The dynamic viscosity η has been evaluated using the relation η = G/(iω), where ω is the angular frequency. The curves of |η| vs temperature of different frequencies converge to a single curve in the glass transition region, and the converged curve is in fair agreement with the data reported in the literature. The dynamic glass transition point, defined as the vibration frequency and temperature at which the curves of the storage modulus G1 and the loss modulus G2 cross each other, obeys the Arrhenius law. The pre-exponential factor and the activation energy of the transition frequency are unusually large, suggesting that collective movements of atoms control the transition.

Keywords: Amorphous solids; Metallic glasses; Glass transition; Viscoelasticity; Viscosity; Rheology

3 Nano Today - In Press, Corrected Proof

Bulk metallic glasses break the mold

4 Journal of Non-Crystalline Solids - Volume 355, Issue 7, Pages 397-458 (15 March 2009)

Kinetic analysis of the isochronal crystallization of Ti40Zr25Ni8Cu9Be18 metallic glass
H.C. Kou, a, , J. Wanga, H. Changa, B. Tanga, J.S. Lia, R. Hua and L. Zhoua

aState Key Laboratory of Solidification Processing, Northwestern Polytechnical University, 127 Youyi Xilu, Xi’an, Shaanxi 710072, PR China

Received 14 August 2008; revised 17 December 2008. Available online 7 February 2009.

Abstract
The isochronal crystallization kinetics of the Ti40Zr25Ni8Cu9Be18 metallic glass has been investigated by differential scanning calorimetry (DSC). Results indicate that the two crystallization events of this metallic glass cannot be well-described by the classic Johnson–Mehl–Avrami (JMA) kinetic equation. The kinetic equation considering the impingement effect has been found more applicable for describing the isochronal crystallization kinetics of this amorphous alloy. Accurate values of kinetic parameters were determined by fitting the theoretical DSC data to experimental curves. The kinetic parameters change in different crystallization stages and show strong heating rate dependence. Reasons of the deviation from the JMA kinetics for the isochronal crystallization of Ti40Zr25Ni8Cu9Be18 metallic glass were discussed.

Keywords: Amorphous metals; Metallic glasses; Crystallization

[ Last edited by hslining on 2009-9-10 at 16:36 ]

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