物理性質隨溫度的變化關系
(中南大學 材料科學與工程學院， 長沙 410083)
摘 要: 結合純金屬單原子(OA)理論和Debye-Grüneisen模型， 采用CALPHAD方法確定的晶格穩(wěn)定參數(shù)， 研究了SGTE純單質數(shù)據(jù)庫中fcc， hcp和bcc 結構Au的原子狀態(tài)、 原子勢能、 原子動能、 原子體積、 體彈性模量和熱膨脹系數(shù)等物理性質隨溫度的變化關系。 結果表明： OA理論得到的fcc-Au電子結構中的共價d電子數(shù)最少， 從而導致fcc-Au具有最大的單鍵半徑以及最大的原子體積；溫度上升過程中， 3種結構的原子單鍵半徑大小順序為： fcc>bcc>hcp， 導致相應的原子體積大小順序為： fcc>bcc>hcp； 3種晶體結構原子勢能大小順序為： fcc<hcp<bcc， 與第一原理VASP程序結果一致； 3種結構的原子動能隨溫度的增加幅度大約是勢能的4.2倍， 溫度上升過程中原子動能的變化遠大于勢能。
關鍵字: fcc； hcp; bcc; Au； 原子狀態(tài)； Debye-Grüneisen模型; CALPHAD方法
LIU Rui-feng, LI Xiao-bo
（School of Materials Science and Engineering,
Central South University, Changsha 410083, China）
Abstract: Combining the One-Atom(OA) theory with Debye-Grüneisen model, the temperature dependence of atomic state, atomic potential and vibrating energy, atomic volume, bulk modulus and linear thermal expansion coefficient of fcc and metastable hcp and bcc Au metals in SGTE database of pure elements was studied with the lattice stability parameters determined by CALPHAD method. The results show that it is the smallest number of covalent electrons in d state of fcc-Au among that of the three structures that leads to the biggest single bond radii and atomic volume. The order of single bond radii of the three structures during the elevation of temperature is fcc>bcc>hcp, and it is the same order for atomic volume. The order of potential energy is fcc<hcp<bcc, and it agrees well with that by VASP program of first principles; the atomic vibrating energy obviously increases with its rate 3.2 times higher than that of potential energy when temperature increases, and the variation of atomic vibrating energy is much higher than that of atomic potential energy during temperature elevation.
Key words: fcc; hcp; bcc; Au； atomic state； Debye-Grüneisen model; CALPHAD method
