Microscopic dynamics perspective on the relationship between Poisson's ratio and ductility of metallic glasses
文献类型：期刊论文
| 作者 | Ngai, KL ; Wang, LM ; Liu, RP ; Wang, WH |
| 刊名 | JOURNAL OF CHEMICAL PHYSICS
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| 出版日期 | 2014 |
| 卷号 | 140期号:4 |
| ISSN号 | 0021-9606 |
| 通讯作者 | Ngai, KL (reprint author), Univ Pisa, Dipartimento Fis, Largo B Pontecorvo 3, I-56127 Pisa, Italy. |
| 中文摘要 | In metallic glasses a clear correlation had been established between plasticity or ductility with the Poisson's ratio nu(Poisson) and alternatively the ratio of the elastic bulk modulus to the shear modulus, K/G. Such a correlation between these two macroscopic mechanical properties is intriguing and is challenging to explain from the dynamics on a microscopic level. A recent experimental study has found a connection of ductility to the secondary beta-relaxation in metallic glasses. The strain rate and temperature dependencies of the ductile-brittle transition are similar to the reciprocal of the secondary beta-relaxation time, tau(beta). Moreover, metallic glass is more ductile if the relaxation strength of the beta-relaxation is larger and tau(beta) is shorter. The findings indicate the beta-relaxation is related to and instrumental for ductility. On the other hand, K/G or nu(Poisson) is related to the effective Debye-Waller factor (i.e., the non-ergodicity parameter), f(0), characterizing the dynamics of a structural unit inside a cage formed by other units, and manifested as the nearly constant loss shown in the frequency dependent susceptibility. We make the connection of f(0) to the non-exponentiality parameter n in the Kohlrausch stretched exponential correlation function of the structural alpha-relaxation function, phi(t) = exp[-(t/tau(alpha))(1-n)]. This connection follows from the fact that both f(0) and n are determined by the inter-particle potential, and 1/f(0) or (1 - f(0)) and n both increase with anharmonicity of the potential. A well tested result from the Coupling Model is used to show that tau(beta) is completely determined by tau(alpha) and n. From the string of relations, (i) K/G or nu(Poisson) with 1/f(0) or (1 - f(0)), (ii) 1/f(0) or (1 - f(0)) with n, and (iii) tau(alpha) and n with tau(beta), we arrive at the desired relation between K/G or nu(Poisson) and tau(beta). On combining this relation with that between ductility and tau(beta), we have finally an explanation of the empirical correlation between ductility and the Poisson's ratio nu(Poisson) or K/G based on microscopic dynamical properties. (C) 2014 AIP Publishing LLC. |
| 资助信息 | NSF of China [51131002, 51271160, 51071138, 51271195, 11274353] |
| 语种 | 英语 |
| 公开日期 | 2015-04-14 |
| 源URL | [http://ir.iphy.ac.cn/handle/311004/59180]  |
| 专题 | 物理研究所_物理所公开发表论文_物理所公开发表论文_期刊论文 |
| 推荐引用方式 GB/T 7714 | Ngai, KL,Wang, LM,Liu, RP,et al. Microscopic dynamics perspective on the relationship between Poisson's ratio and ductility of metallic glasses[J]. JOURNAL OF CHEMICAL PHYSICS,2014,140(4). |
| APA | Ngai, KL,Wang, LM,Liu, RP,&Wang, WH.(2014).Microscopic dynamics perspective on the relationship between Poisson's ratio and ductility of metallic glasses.JOURNAL OF CHEMICAL PHYSICS,140(4). |
| MLA | Ngai, KL,et al."Microscopic dynamics perspective on the relationship between Poisson's ratio and ductility of metallic glasses".JOURNAL OF CHEMICAL PHYSICS 140.4(2014). |
入库方式： OAI收割
来源：物理研究所
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