Calculations of dominant factors of glass-forming ability for metallic glasses from viscosity
Calculations of dominant factors of glass-forming ability for metallic glasses from viscosity
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DOI：
10.1016/j.msea.2003.10.199
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发表时间：
2004-07
期刊：
影响因子：
6.4
通讯作者：
A. Takeuchi;A. Inoue
中科院分区：
文献类型：
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作者：
A. Takeuchi;A. Inoue
提出了以粘度为主要参数的计算模型，用于估计三个玻璃形成能力（GFA）因素：形成玻璃相的临界冷却速率（Rc）、降低的玻璃化转变温度（Tg/Tm）和过冷液体范围（ΔTxTx−Tg），其中Tg、Tman和Tx分别是玻璃化温度、熔化温度和结晶温度。基于均匀成核和生长理论，通过构建金属玻璃结晶的时间变换图，分析了Rc和Tg/Tm。另一方面，ΔTx是根据Beukel和Sietsma提出的自由体积理论计算的，然后与从时间变换曲线计算出的Rc相关。对粘度用 Vogel-Fulcher-Tammann 方程或 Doolittle 方程表示的 Fe-、Pd-、Pt-、Zr-、Mg 基金属玻璃进行了计算。 Rc−Tg/Tman 和 Rc−ΔTx 图中总结的计算结果与实验数据定性一致。结果表明，金属玻璃的所有 GFA 系数都可以根据粘度计算出来。这些结果表明粘度是确定 Rc、Tg/Tman 和 ΔTx 的关键参数。
The calculation models in which the viscosity is used as a main parameter are proposed for the estimation of the three glass-forming ability (GFA) factors: critical cooling rate (Rc) for formation of glassy phase, reduced glass transition temperature (Tg/Tm) and supercooled liquid range (ΔTxTx−Tg), where Tg, Tmand Txare the glass transition, melting and crystallization temperature, respectively. The Rcand Tg/Tmwere analyzed on the basis of the homogeneous nucleation and growth theory by the construction of a time-transformation diagram for the crystallization of metallic glass. On the other hand, ΔTxwas calculated on the basis of a free volume theory proposed by Beukel and Sietsma, and then was related with Rccalculated from the time–transformation curve. The calculations were carried out for Fe-, Pd-, Pt-, Zr-, Mg-based metallic glasses for which the viscosity is expressed by Vogel–Fulcher–Tammann equation or the Doolittle equation. The calculated results summarized in Rc−Tg/Tmand Rc−ΔTxdiagrams agree with the experimental data qualitatively. It was shown that all the GFA factors of metallic glasses can be calculated from viscosity. These results indicate that the viscosity is the key parameter for the determinations of Rc, Tg/Tmand ΔTx.