物理学报
物理學報
물이학보
2013年
3期
217-222
,共6页
分子动力学模拟%纳米Cu%等温晶化%临界尺寸
分子動力學模擬%納米Cu%等溫晶化%臨界呎吋
분자동역학모의%납미Cu%등온정화%림계척촌
molecular dynamics simulation%Cu nanocluster%isothermal crystallization%critical size
采用分子动力学方法和镶嵌原子势,模拟了4000个Cu原子和13500个Cu原子(简称Cu4000和Cu13500)组成的纳米颗粒以及块体Cu的等温晶化过程.通过对这些颗粒在晶化过程中结构和动力学行为的分析研究,发现低温时,不同尺寸的纳米Cu颗粒均出现多步晶化,且晶化时间的分布曲线远比高温时范围大;除了温度,颗粒尺寸对晶化行为也有重要的影响,尺寸越大,晶化时间越长,最终的晶化程度越高;但是晶化时间随尺寸增大而增加的趋势不会一直持续,发现存在一个临界尺寸rc,小于rc时,晶化时间随颗粒尺寸增大而增加,大于rc时,晶化时间随尺寸增大而减小.
採用分子動力學方法和鑲嵌原子勢,模擬瞭4000箇Cu原子和13500箇Cu原子(簡稱Cu4000和Cu13500)組成的納米顆粒以及塊體Cu的等溫晶化過程.通過對這些顆粒在晶化過程中結構和動力學行為的分析研究,髮現低溫時,不同呎吋的納米Cu顆粒均齣現多步晶化,且晶化時間的分佈麯線遠比高溫時範圍大;除瞭溫度,顆粒呎吋對晶化行為也有重要的影響,呎吋越大,晶化時間越長,最終的晶化程度越高;但是晶化時間隨呎吋增大而增加的趨勢不會一直持續,髮現存在一箇臨界呎吋rc,小于rc時,晶化時間隨顆粒呎吋增大而增加,大于rc時,晶化時間隨呎吋增大而減小.
채용분자동역학방법화양감원자세,모의료4000개Cu원자화13500개Cu원자(간칭Cu4000화Cu13500)조성적납미과립이급괴체Cu적등온정화과정.통과대저사과립재정화과정중결구화동역학행위적분석연구,발현저온시,불동척촌적납미Cu과립균출현다보정화,차정화시간적분포곡선원비고온시범위대;제료온도,과립척촌대정화행위야유중요적영향,척촌월대,정화시간월장,최종적정화정도월고;단시정화시간수척촌증대이증가적추세불회일직지속,발현존재일개림계척촌rc,소우rc시,정화시간수과립척촌증대이증가,대우rc시,정화시간수척촌증대이감소.
We investigate the isothermal crystallizations of nanoparticles composed, respectively, of 4000 Cu atoms (Cu4000) and 13500 Cu atoms (Cu13500), and bulk Cu according to on embedded atom model, using molecular dynamics simulations. We note that different sizes of Cu nanoparticles display multistep crystallization at low temperature, and their crystallization time distribution is wider than at high temperature, shown by analyzing the structural and dynamic properties of isothermal crystallization. Moreover, the size of particle plays an important role in the crystallization process. The larger the size, the longer the crystallization time is. However, we find that there is a critical size rc. The crystallization time increases with particle size increasing when the size is less than rc. On the contrary, when the size is more than rc, the crystallization time decreases with particle size increasing.
