THERMODYNAMIC STUDY AND CELLULAR AUTOMATON SIMULATION OF THERMAL STABILITY IN NANOCRYSTALLINE SmCo7 ALLOY
The precise quantitative relationship between the excess volume at the grain boundary and the nanograin size in nanocrystalline alloys was deduced.The fundamental thermodynamic functions of nanocrystalline alloys were derived as functions of the nanograin size and the temperature.By using the SmCo7 alloy as an example,the thermal stability of the nanocrystalline alloy,as well as its evolution characteristics,was studied based on the calculated excess Gibbs free energy of nanograin boundaries.The results show that the nanostructure with grain size below a critical value that corresponds to the maximum excess Gibbs free energy can have higher thermal stability than a coarser nanograin structure.Once the grain size is larger than the critical value,the nanostructure may lose its stability and undergo discontinuous grain growth.By combining the nanothermodynamic model with the cellular automation algorithm,the quantitative and visual simulations of nanograin growth in nanocrystalline SmCo7 alloy were performed.The nanograin growth behavior described by the two approaches are consistent with each other,which validates the declaration of the thermal stability of nanocrystalline alloys by the present thermodynamic study.
nanothermodynamics SmCo7 alloy thermal stability cellular automaton simulation
Yang Zhang Xiaoyan Song Wenwu Xu Zhexu Zhang
College of Materials Science and Engineering,Key Lab of Advanced Functional Materials,Education Ministry of China,Beijing University of Technology,Beijing 100124,China
国际会议
北京
英文
310-317
2011-10-19（万方平台首次上网日期，不代表论文的发表时间）