點缺陷對B2-CoSc化合物物性影響的第一性原理研究
發(fā)布時間:2018-05-16 10:21
本文選題:B-CoSc金屬間化合物 + 第一性原理; 參考:《中國有色金屬學(xué)報》2017年08期
【摘要】:利用第一性原理的Castep軟件,對B2型金屬間化合物Co Sc的16種點缺陷的熱力學(xué)參數(shù)、電子結(jié)構(gòu)和彈性常數(shù)進(jìn)行計算,分析16種點缺陷存在的類型及對化合物力學(xué)性能的影響。結(jié)果表明:Co單空位形成熱和結(jié)合能分別是-6.78 e V和-0.43 e V,Co單空位化合物最容易形成、穩(wěn)定性最好;其次是Co單反位化合物,形成熱和結(jié)合能分別是-6.152 e V和2.504 e V。從而得出16種點缺陷最穩(wěn)定存在形式是Co空位和Co反位;存在的組態(tài)是Co單空位、Co雙空位、Co三空位和Co雙反位。由電子態(tài)密度圖中的費米能級和贗能隙也定性判斷出,Co空位和反位缺陷化合物比Sc空位和反位缺陷化合物穩(wěn)定。計算6種點缺陷的泊松比?可知,Co三空位的化合物金屬鍵最強(qiáng)、塑性最好。與完整的Co Sc金屬間化合物塑性相比,有空位缺陷的金屬間化合物塑性得到提高。
[Abstract]:The thermodynamic parameters, electronic structure and elastic constants of 16 point defects of B2 type intermetallic compound Co SC were calculated by first-principle Castep software. The existing types of 16 point defects and their effects on the mechanical properties of the compounds were analyzed. The results show that the formation heat and binding energy of the single vacancy are -6.78e V and -0.43 EV, respectively, and the stability is the best, and the formation heat and binding energy are -6.152e V and 2.504 EV, respectively, and the formation heat and binding energy are -6.152e V and 2.504 EV, respectively. Thus, it is concluded that the most stable forms of 16 point defects are Co vacancies and Co antipositions, and the configuration of these defects is Co single vacancy Co double vacancies and Co double inversion positions. The Fermi energy levels and pseudo-energy gaps in the electron density diagram also show that the Co vacancy and antipotential defect compounds are more stable than SC vacancy and antipotential defect compounds. To calculate the Poisson's ratio of six point defects? It can be seen that the metal bond of the compound is the strongest and the plasticity is the best. Compared with the intact Co SC intermetallic compounds, the plasticity of the intermetallic compounds with vacancy defects is improved.
【作者單位】: 河南理工大學(xué)材料科學(xué)與工程學(xué)院;
【基金】:國家自然科學(xué)基金資助項目(51271073,51301063)~~
【分類號】:TG111.2
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