中国有色金属学报
中國有色金屬學報
중국유색금속학보
The Chinese Journal of Nonferrous Metals
2015年
10期
2863-2870
,共8页
液态金属Cu%分子动力学模拟%Q-SC多体势%微观结构演变%成核%生长
液態金屬Cu%分子動力學模擬%Q-SC多體勢%微觀結構縯變%成覈%生長
액태금속Cu%분자동역학모의%Q-SC다체세%미관결구연변%성핵%생장
liquid metal Cu%molecular dynamics simulation%Q-SC multi-body potential%microstructure evolution%nucleation%growth
采用分子动力学方法和Quantum Sutton-Chen多体势，对2万个液态金属铜(Cu)原子在两个不同冷速凝固过程中其微观团簇结构的形成特性以及晶体的成核生长进行模拟。运用双体分布函数、Honeycutt-Andersen(HA)键型指数法、原子团类型指数法(CTIM-2)和可视化分析等方法，对凝固过程中微观结构转变和原子团簇的微观结构演变特性进行分析。结果表明：冷却速率为4.0×1012 K/s和2.0×1012 K/s时，系统形成以1421、1422键型或由这两种键型构成的面心立方(FCC)(12000120)和六角密集(HCP)基本原子团(1200066)为主体的晶体结构；尤其是由1421键型构成的面心立方(12000120)基本原子团在晶体生长和对微观结构演变的影响占主导地位。两种冷却速度下的结晶温度分别为673 K和773 K，即冷却速度越慢，结晶温度越高；系统最终形成了由FCC和HCP组成的混合晶体结构，但以FCC晶体结构为主；FCC(12000120)基本原子团在慢速低温时具有较好的遗传特性，基本原子团之间很容易连接在一起构成较大的纳米级大团簇结构。
採用分子動力學方法和Quantum Sutton-Chen多體勢，對2萬箇液態金屬銅(Cu)原子在兩箇不同冷速凝固過程中其微觀糰簇結構的形成特性以及晶體的成覈生長進行模擬。運用雙體分佈函數、Honeycutt-Andersen(HA)鍵型指數法、原子糰類型指數法(CTIM-2)和可視化分析等方法，對凝固過程中微觀結構轉變和原子糰簇的微觀結構縯變特性進行分析。結果錶明：冷卻速率為4.0×1012 K/s和2.0×1012 K/s時，繫統形成以1421、1422鍵型或由這兩種鍵型構成的麵心立方(FCC)(12000120)和六角密集(HCP)基本原子糰(1200066)為主體的晶體結構；尤其是由1421鍵型構成的麵心立方(12000120)基本原子糰在晶體生長和對微觀結構縯變的影響佔主導地位。兩種冷卻速度下的結晶溫度分彆為673 K和773 K，即冷卻速度越慢，結晶溫度越高；繫統最終形成瞭由FCC和HCP組成的混閤晶體結構，但以FCC晶體結構為主；FCC(12000120)基本原子糰在慢速低溫時具有較好的遺傳特性，基本原子糰之間很容易連接在一起構成較大的納米級大糰簇結構。
채용분자동역학방법화Quantum Sutton-Chen다체세，대2만개액태금속동(Cu)원자재량개불동랭속응고과정중기미관단족결구적형성특성이급정체적성핵생장진행모의。운용쌍체분포함수、Honeycutt-Andersen(HA)건형지수법、원자단류형지수법(CTIM-2)화가시화분석등방법，대응고과정중미관결구전변화원자단족적미관결구연변특성진행분석。결과표명：냉각속솔위4.0×1012 K/s화2.0×1012 K/s시，계통형성이1421、1422건형혹유저량충건형구성적면심립방(FCC)(12000120)화륙각밀집(HCP)기본원자단(1200066)위주체적정체결구；우기시유1421건형구성적면심립방(12000120)기본원자단재정체생장화대미관결구연변적영향점주도지위。량충냉각속도하적결정온도분별위673 K화773 K，즉냉각속도월만，결정온도월고；계통최종형성료유FCC화HCP조성적혼합정체결구，단이FCC정체결구위주；FCC(12000120)기본원자단재만속저온시구유교호적유전특성，기본원자단지간흔용역련접재일기구성교대적납미급대단족결구。
A simulation study was performed on the formation properties of micro-cluster structures and nucleation and growth of crystals during solidification process of 20000 liquid metal Cu atoms at two different cooling rates by adopting the molecular dynamics method and Quantum Sutton-Chen multi-body potential. The pair distribution function, the bond-type index method of Honeycutt-Andersen(HA), cluster-type index method(CTIM-2)and visualization analysis were used to analyze and study the transition of microstructures and evolution properties of micro-cluster configurations during solidification process. The results show that the crystal structures form mainly with the 1421 and 1422 bond-types or the FCC(12 0 0 0 12 0) basic cluster, and the HCP(12 0 0 0 6 6) basic cluster being composed of the two bond-types at the cooling rates of 4.0×1012 K/s and 2.0×1012 K/s. Especially, the FCC(12 0 0 0 12 0) basic clusters consisting of 1421 bond-type occupy a dominant position in crystal-growth and the effect of microstructures evolution. Meanwhile, it has been found that the temperatures of crystallization are 673 K and 773 K under two cooling rates, respectively. Namely, the lower the cooling speed is, the higher the crystal temperature is, and finally the system forms the crystal and amorphous mixed coexistence structures of FCC ad HCP, but the FCC crystal structures is major. When the cooling rates and temperature are lower, the FCC(12 0 0 0 12 0) basic cluster posseses better genetic characteristic, and the basic clusters are easier to form bigger nano-cluster structure by bonding together.
