Preparation of Zr 60 Ni 21 Al 19 bulk metallic glass and compression behavior under high pressure
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J. Liu Beijing Synchrotron Radiation Laboratory (BSRF), Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, People’s Republic of China (Received 15 January 2008; accepted 17 March 2008)
Zr60Ni21Al19 metallic glass rod, with a diameter of 8 mm, is manufactured by copper mold casting. The as-cast bulk metallic glass (BMG) exhibits nearly zero plastic strain, but a high strength of 1.88 GPa. The compression behavior of this new zirconium-base ternary BMG under high pressure at ambient temperature in a diamond-anvil cell instrument has been unraveled using energy dispersive x-ray diffraction with a synchrotron radiation source. The investigation shows that the amorphous structure of Zr60Ni21Al19 is stable under pressures up to 24.5 GPa at room temperature. According to the Bridgman equation of state, the bulk modulus B0 ⳱ 96 GPa has been obtained.
I. INTRODUCTION
Since the development of bulk metallic glasses (BMGs) during the early 1990s,1,2 multicomponent Zrbased BMGs, with a larger geometry by a conventional casting process with a low cooling rate,3,4 are being widely studied because they exhibit a range of interesting properties. These properties include high strengths, ductility in compression, low coefficients of friction, high wear resistance, and high corrosion resistances. 5–8 “Amorphous” represents a state of solid metastability and metallic glasses including BMGs, which have metallic bonds that are nondirectional in nature and are distinctly different from the traditional network-forming glasses. BMGs, with highly random packed microstructure, are similar to that of a liquid3; their excellent glassforming ability and special mechanical and physical properties9,10 have a close relation with their lack of any long-range order. Compression behavior of materials is dependent on interatomic potential and related to atomic configurations.11,12 The structural evaluation of metallic glass contains a series of continuous change on the atomic level, which is linked to atomic short range ordering (SRO) or middle range ordering (MRO).13,14 With high pressure as a thermodynamic variable, the temperature can have a significant effect on the chemical and physical properties of matter. Therefore it is important in
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Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2008.0310 2346
http://journals.cambridge.org
J. Mater. Res., Vol. 23, No. 9, Sep 2008 Downloaded: 13 Mar 2015
practice and theory to investigate structure of the amorphous alloys under high pressure.15 Wang et al. have investigated the equation of state of ZrTiCuNiBe BMG under low pressure (0–4.5 GPa).4,16 However, because binary and ternary BMGs are relatively new materials, little is known about some aspects of the materials under high pressure. In particular, the measurements of compression properties are of great importance to understand the relationship between unique mechanical properties and configurational changes under pressure. In this article, bulk Zr60Ni21Al19 metallic glass rod, wi
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