(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083； 2. 中南大學(xué) 冶金科學(xué)與工程學(xué)院，長沙 410083； 3. 中南大學(xué) 粉末冶金國家重點(diǎn)實(shí)驗(yàn)室，長沙 410083)
摘 要: 采用最小二乘法對SGTE純單質(zhì)數(shù)據(jù)庫中金屬M(fèi)g的Gibbs能表達(dá)式進(jìn)行了重新評估，得到了比SGTE數(shù)據(jù)庫更精確的結(jié)果；同時，將SGTE數(shù)據(jù)庫的晶格穩(wěn)定參數(shù)外推至0 K，與第一原理總能贗勢平面波方法的結(jié)果進(jìn)行了對比，發(fā)現(xiàn)第一原理的晶格穩(wěn)定參數(shù)結(jié)果為∆Gbcc−hcp＞∆Gfcc−hcp＞0，與SGTE外推結(jié)果一致。同時，研究還發(fā)現(xiàn)：第一原理總能平面波贗勢方法計(jì)算的hcp-、fcc-和bcc-Mg的晶格常數(shù)和原子體積比實(shí)驗(yàn)值以及投影綴加波方法得到的結(jié)果偏大，結(jié)合能出現(xiàn)了完全相反的結(jié)果, 并且3種結(jié)構(gòu)的部分s態(tài)電子轉(zhuǎn)化為p態(tài)電子形成了更強(qiáng)的化學(xué)鍵。
關(guān)鍵字: Mg；Gibbs能；電子結(jié)構(gòu)；晶格穩(wěn)定性；第一原理
（1 School of Materials Science and Engineering, Changsha 410083, China; 2. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China; 3. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The correction of transition data and reassessment of the parameters of Gibbs energy of elemental Mg were performed with the least-square method and the results agree more accurately with JANAF data than those of SGTE database. At the same time, the lattice stability parameters obtained by CALPHAD method in SGTE database were extrapolated to 0 K, and these results were compared with those of total energy plane wave pseudopotential method in first principles. It is found that the result of first principles agrees completely with that of SGTE, ∆Gbcc−hcp＞∆Gfcc−hcp＞0. Besides, it is found that the results of lattice constants and atomic volumes of hcp-, fcc- and bcc-Mg calculated by total energy plane wave pseudopotential method are much larger than experimental data and those of projector augmented wave method in first principles. The contrary case occurs in total energy. And part of s state electrons in atoms were changed into p state electrons in crystals to form stronger chemical bonding.
Key words: Mg; Gibbs energy; electronic structure; lattice stability; first principles
