Thermodynamic Study on Phase Stability in the Nanocrystalline Sm-Co System
- 作者：Wenwu XuXiaoyan SongErdong LiJun WeiLingmei Li
- 会议时间：2008-11-01
- 关键词：纳米热力学 ; 钐钴合金 ; 相转移 ; 相稳定性
- 作者单位：Wenwu Xu(collegc of Materials science and Engmeering,Key Laboratory of Advanccd FunctionaI Materials,chinesc Ministry of Education,Beijing University ofTechnology,Beijing 100124,China)Xiaoyan Song,Erdong Li(collegc of Materials science and Engmeering,Key Laboratory of Advanccd FunctionaI Materials,chinesc Ministry ofEducation,Beijing University ofTechnology,Beijing 100124,China)Jun Wei,Lingmei Li(collegc of Materials science and Engmeering,Key Laboratory of Advanccd FunctionaI Materials,chinesc Ministry ofEducation,Beijing University of Technology,Beijing 100124,China)
- 母体文献：第十四届全国相图会议暨国际相图与材料设计研讨会论文集
- 会议名称：第十四届全国相图会议暨国际相图与材料设计研讨会
- 会议地点：长沙
- 主办单位：中国物理学会
- 语种：chi
摘要
A nanoscale thermodynamic model was developed to describe the phase stability and the phase transition features in nanocrystalline(NC)alloys.Using NC Sm-Co alloy aS an example,the thermodynamic properties of different stoichiometric alloy phases were systematically calculated.Particularly,the temperature-dependence of the Gibbs free energy of each alloy phase with different nano-grain sizes were provided.Based on the model calculations,the relative stabilities of different phases in NC Sm-Co system were analyzed.It WaS shown by the calculation results that at the room temperature,when the nano-grain size is reduced to below certain critical values,the Gibbs free energy of SmC05,SmC03 and SmC02 will become positive,which implies that these phases cannot stably exist at room temperature,which is distinctly different from the phase stability in conventional coarse-grained polycrystalline alloys.The experimental studies performed in our group,which WaS focused ON preparation and characterization of stoichiometric NC Sm-Co alloys,confirmed the present nanoscale thermodynamic predictions.