First principles calculations of nucleation free energy change for precipitation.

沉淀成核自由能变化的第一原理计算。

• 批准号: 17560587
• 负责人: NISHITANI Shigeto R.
• 金额: $ 2.11万
• 依托单位: Kwansei Gakuin University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17560587/
• 关键词: Quasi harmonic approximation; phonon dispersion; Fe-Cu alloy; irradiation; vacancy; 振動エネルギー; 希薄固溶エンタルピー; 空孔エネルギー; フレンケル法; モンテカルロ法; 並列計算

The head investigator has been proposing the first principles calculations of the free energy change for the precipitate nucleation. In this research, the wide range of the applications of this newly proposed method has been explored. The vibrational effects have been included by the phonon density of states obtained by the first principle calculation, which is based on the the quasi-harmonic approximation. The applications on ternary additionals and the vacancy effects were also investigated.The following results are obtained and published in the journals.(1)Effectively calculating the stiffness around the precipitates, the free energy change due to the vibrational effects is precisely calculated, and revealed to contribute the two third of the total energy change.(2)The origin of the expansion of the effective radius of Cu in Fe matrix is revealed to be the repulsive interactions between Fe and Cu. All the trend of the effective radii in 3d transition metals is clearly shown to relate with the dilution limit enthalpy of formation.(3)Ni additions, for the cancellation of the high repuslive interaction between Fe and Cu, prefer to locate at the interface between Cu precipitate and Fe matrix.(4)The vacancy prefers to locate inside the Cu precipitates, which is interpreted by the vacancy formation energy difference between pure Cu and pure Fe.

首席研究员一直在提出沉淀成核自由能变化的第一原理计算。在这项研究中，探索了这种新提出的方法的广泛应用。振动效应已包含在基于准谐波近似的第一原理计算所获得的声子态密度中。还研究了三元附加物和空位效应的应用。获得了以下结果并发表在期刊上。（1）有效计算析出物周围的刚度，精确计算由于振动效应引起的自由能变化，并揭示贡献了总能量变化的三分之二。(2)Fe基体中Cu有效半径膨胀的根源是Fe和Cu之间的排斥相互作用。 3d过渡金属中有效半径的所有趋势都清楚地表明与稀释极限生成焓有关。（3）Ni的添加，为了消除Fe和Cu之间的高排斥相互作用，更倾向于位于Fe和Cu之间的界面处。 Cu析出物和Fe基体。(4)空位更倾向于位于Cu析出物内部，这可以通过纯Cu和纯Fe之间的空位形成能差异来解释。

项目成果

First principle calculations of nucleation free energy change for bcc Cu precipitates in Fe-Cu system.

Fe-Cu 体系中 bcc Cu 析出物形核自由能变化的第一原理计算。

• 发表时间: 2005
• 期刊: Solid-Solid Phase Transformations in Inorganic Materials 2005(Editors : James M.Howe, David E.Laughlin, Jong K.Lee, Ultrich Dahmen, and William A.Soffa(TMS)(The Minerals, Metals & Materials Society)2005 vol.11
• 作者: Masayuki Nishida;Takao Hanabusa;Yasukazu Ikeuchi;Masayuki Nishida;西谷滋人;Shigeto R.Nishitani;Shigeto R.Nishitani;Shigeto R.Nishitani;西谷滋人;Shigeto R.Nishitani;Shigeto R.Nishitani;Shigeto R.Nishitani;Shigeto R.Nishitani;Shigeto R.Nishitani;Koretaka Yuge;Shigeto R.Nishitani;Shigeto R.Nishitani;Koretaka Yuge;Shigeto R.Nishitani
• 通讯作者: Shigeto R.Nishitani

Vacancy effect on the precipitate nucleation in Fe-Cu alloy

空位对Fe-Cu合金中析出相形核的影响

• 发表时间: 2006
• 期刊: Proceedings for the 3rd International Conference of Multiscale Materials Modeling(Ed by P.Gumbsch)(Fraunfofer IRB Veralag) ISBN-13:978-3-8167-7206-4
• 作者: Masayuki Nishida;Takao Hanabusa;Yasukazu Ikeuchi;Masayuki Nishida;西谷滋人;Shigeto R.Nishitani;Shigeto R.Nishitani;Shigeto R.Nishitani;西谷滋人;Shigeto R.Nishitani
• 通讯作者: Shigeto R.Nishitani

バルク中でのナノサイズ熱力学と相安定性

纳米尺寸热力学和体相稳定性

• 发表时间: 2007
• 期刊: まてりあ 46・3
• 作者: Masayuki Nishida;Takao Hanabusa;Yasukazu Ikeuchi;Masayuki Nishida;西谷滋人
• 通讯作者: 西谷滋人

First-principles study of the effect of lattice vibrations on Cu nucleation free energy in Fe-Cu alloys

• DOI: 10.1103/physrevb.72.174201
• 发表时间: 2005-11
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Koretaka Yuge;Atsuto Seko;I. Tanaka;S. Nishitani

Free Energy Calculations of Precipitate Nucleation

沉淀成核的自由能计算

• 发表时间: 2007
• 期刊: Materials Science Forum 539-543
• 作者: Masayuki Nishida;Takao Hanabusa;Yasukazu Ikeuchi;Masayuki Nishida;西谷滋人;Shigeto R.Nishitani
• 通讯作者: Shigeto R.Nishitani