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采用分子动力学方法结合量子修正Sutton-Chen型多体力场,对由{100}面和{111}面构成的十四面体Pt纳米晶在升温过程中的热稳定性和熔化机制进行了计算机模拟研究,并引入统计半径和Lindemann指数来分析它的结构和形状演化过程.结果表明:该纳米晶在1500K时形状开始发生变化,并在1700K时转变为球形.铂纳米晶粒在1500K时开始出现表面预熔,在1650K时表面完全熔化并开始向内部传播,最终在1730K时整体熔化为液态粒子.表面预熔的出现对形状转变的发生是有利的.
The thermal stability and melting mechanism of tetradecahedron Pt nanocrystals composed of {100} planes and {111} planes were investigated by molecular dynamics method combined with quantum correction of Sutton-Chen type multi-body field. And the statistical analysis and the Lindemann index were used to analyze the structure and shape evolution of the nanocrystal.The results show that the nanocrystal begins to change its shape at 1500K and turns into a spherical shape at 1700 K. Platinum nanocrystal begins at 1500K Surface premelting occurs, and at 1650 K, the surface completely melts and begins to propagate internally, eventually melting to liquid particles as a whole at 1730 K. The appearance of surface premelt is advantageous for shape transitions.