采用基于密度泛函理论的Dmol 4.1程序,从合金形成热、结合能、热力学性能和态密度等方面,研究Sb、Bi合金化提高Mg-Al系合金抗蠕变性能的影响机理.结果表明:Sb、Bi分别置换Mg-Al系合金Mg17Al12相中Mg(Ⅰ),Mg(Ⅱ),Mg(Ⅲ)和Al原子时,仅Sb置换Mg17Al12相中Mg(Ⅰ),Mg(Ⅱ) 原子,Bi置换Mg17Al12相中Mg(Ⅰ)原子能形成稳定的Mg17Al12固溶体结构,这表明Sb、Bi在Mg17Al12中固溶量有限.进一步比较合金化形成稳定的固溶体结构,发现Sb、Bi合金化后,固溶体结构的稳定性比未合金化时增强,其中,Sb置换Mg17Al12相中Mg(Ⅱ)原子时,其结构稳定性最高,其次Sb置换Mg17Al12相中Mg(Ⅰ)原子,再次Bi置换Mg17Al12相中Mg(Ⅰ)原子;而析出金属间化合物Mg3Bi2和Mg3Sb2,比相应合金化Mg17Al12固溶体的结构更稳定.不同温度下热力学性能的计算发现,合金体系中形成了结构稳定性高的Sb、Bi合金化Mg17Al12固溶体以及金属间化合物Mg3Sb2和Mg3Bi2,这些相高的结构稳定性并不因温度的升高而消失,其结构稳定性仍比Mg17Al12相高,因此Sb、Bi合金化提高了Mg-Al系合金的抗蠕变性能.电子态密度的分析结果进一步表明,Mg-Al系合金中相结构稳定性提高的主要原因在于:Sb、Bi合金化后,体系费米能级以下低能级区成键电子数的增多,其来源主要是Mg(s)、Mg(p)、Al(p)、Bi(d)和Sb(d)的价电子.
参考文献
| [1] | LUO A;PEKGULERYUZ M O .Cast magnesium alloys for elevated temperature application[J].Journal of Materials Science,1994,29(20):5259-5271. |
| [2] | 袁广银,曾小勤,吕宜振,丁文江,孙扬善.锑合金化对镁铝基合金力学性能的改善作用[J].材料工程,2001(04):10-15. |
| [3] | 袁广银,张为民,孙扬善.Mg-Al基合金加铋合金化对其力学性能的改善作用[J].东南大学学报（自然科学版）,1999(03):115. |
| [4] | 张国英,张辉,方戈亮,李昱材.Bi,Sb合金化对AZ91镁合金组织、性能影响机理研究[J].物理学报,2005(11):5288-5292. |
| [5] | DU Wen-wen;SUN Yang-shan;MIN Xue-gang .Influence of Ca addition on valence electron structure of Mg_(17)Al_(12)[J].Transactions of Nonferrous Metals Society of China,2003(6):1274-1279. |
| [6] | 闵学刚,杜温文,薛烽,孙扬善.Ca提高Mg17Al12相熔点的现象及EET理论分析[J].科学通报,2002(02):109-112. |
| [7] | PERDEW J P;BURKE K;ERNZERHOF M .Generalized gradient approximation made simple[J].Physical Review Letters,1996,77(18-28):3865-3868. |
| [8] | PACK J D;MONKHORST H J .Special points for Brillouin-zone integrations-A reply[J].Physical Review B:Condensed Matter,1977,16(4-15):1748-1749. |
| [9] | DELLEY B .Analytic energy derivatives in the numerical local-density-functional approach[J].Journal of Chemical Physics,1991,94(11):7245-7250. |
| [10] | N.I.Medvedeva;Yu. N Gornostyrev;D.L.Novikov .Ternary site preference energies, size misfits and solid solution hardening in NiAl and FeAl[J].Acta materialia,1998(10):3433-3442. |
| [11] | Sahu BR .Electronic structure and bonding or ultralight LiMg[J].Materials Science & Engineering, B. Solid-State Materials for Advanced Technology,1997(1):74-78. |
| [12] | ZHOU D W;PENG P;LIU J S .Energetics,electronic structure and structure stability of the calcium alloying Mg17Al12 phase from first principles calculations[J].Materials Science,2007,25(01):145-153. |
| [13] | Y. SONG;Z. X. GUO;R. YANG .FIRST PRINCIPLES STUDY OF SITE SUBSTITUTION OF TERNARY ELEMENTS IN NiAl[J].Acta materialia,2001(9):1647-1654. |
| [14] | Li CH.;Hoe JL.;Wu P. .Empirical correlation between melting temperature and cohesive energy of binary Laves phases[J].The journal of physics and chemistry of solids,2003(2):201-212. |
| [15] | ZUBOV V I;TRETIAKOV N P;TEIXEIRA RABELO J N;SANCHEZ ORTIZ J F .Calculations of the thermal expansion,cohesive energy and thermodynamic stability of a van der Waals crystal-fullerene C60[J].Physics Letters A,1995,198(5-6):470. |
| [16] | Ishii Y.;Fujiwara T. .Electronic structures and cohesion mechanism of Cd-based quasicrystals[J].Journal of Non-Crystalline Solids: A Journal Devoted to Oxide, Halide, Chalcogenide and Metallic Glasses, Amorphous Semiconductors, Non-Crystalline Films, Glass-Ceramics and Glassy Composites,2002(0):494-497. |
| [17] | S.B.Fagan;R.Mota;R.J.Baierle;G.Paiva;A.J.R.da Silva;A.Fazzio .Stability investigation and thermal behavior of a hypothetical silicon nanotube[J].Journal of Molecular Structure. Theochem: Applications of Theoretical Chemistry to Organic, Inorganic and Biological Problems,2001(1/3):101-106. |
| [18] | C.L. Fu .Phase stability, bonding mechanism, and elastic constants of Mo5Si3 by first-principles calculation[J].Intermetallics,1999(2):179-184. |
| [19] | NYLEN J;GARCIA F J;MOSEL B D .Structure relationships,phase stability and bonding of compounds PdSnn (n=2,3,4)[J].Solid State Sciences,2004,6(01):147-155. |
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