吉林大学学报（理学版）
吉林大學學報（理學版）
길림대학학보（이학판）
JOURNAL OF JILIN UNIVERSITY(SCIENCE EDITION)
2014年
5期
1039-1043
,共5页
铜纳米线%材料断裂%位错运动%微观形貌
銅納米線%材料斷裂%位錯運動%微觀形貌
동납미선%재료단렬%위착운동%미관형모
Cu nanowire%material fracture%dislocation motion%micro-morphology
基于经典力学势函数的分子动力学模拟方法研究铜纳米线的拉伸断裂过程，并分析断裂前应力、应变和位错行为的关系及断裂后的形貌演化。结果表明：纳米线两端的锥形结构可阻塞位错运动，从而提高其断裂强度；断裂后断口处尖锐的尖端结构形貌会发生自发的回缩和钝化，该过程是尖端上储存的弹性能和的高能结构(如孤立原子、孪晶界和表面弯折等)的自我修复，最终在表面上形成许多能量较低的(111)小平面所致；其物理机理是在温度激活下的能量最小化过程。
基于經典力學勢函數的分子動力學模擬方法研究銅納米線的拉伸斷裂過程，併分析斷裂前應力、應變和位錯行為的關繫及斷裂後的形貌縯化。結果錶明：納米線兩耑的錐形結構可阻塞位錯運動，從而提高其斷裂彊度；斷裂後斷口處尖銳的尖耑結構形貌會髮生自髮的迴縮和鈍化，該過程是尖耑上儲存的彈性能和的高能結構(如孤立原子、孿晶界和錶麵彎摺等)的自我脩複，最終在錶麵上形成許多能量較低的(111)小平麵所緻；其物理機理是在溫度激活下的能量最小化過程。
기우경전역학세함수적분자동역학모의방법연구동납미선적랍신단렬과정，병분석단렬전응력、응변화위착행위적관계급단렬후적형모연화。결과표명：납미선량단적추형결구가조새위착운동，종이제고기단렬강도；단렬후단구처첨예적첨단결구형모회발생자발적회축화둔화，해과정시첨단상저존적탄성능화적고능결구(여고립원자、련정계화표면만절등)적자아수복，최종재표면상형성허다능량교저적(111)소평면소치；기물리궤리시재온도격활하적능량최소화과정。
To explore the fracture mechanism of metal nanowires,a fracture process of Cu nanowire upon stretch was theoretically studied by molecular dynamic (MD)simulations based on embedded-atom method (EAM)potential.The relationship between stress,strain and dislocation before fracture as well as the morphology evolution after fracture was analyzed.The results demonstrate that the tips on the two ends of the nanowire can stuck the dislocation motion.Then the stacking fault by the first partial dislocation could be annihilated by a full dislocation formed by another partial dislocation.This process can thus enhance the fracture strength.The sharp structure after fracture can retract and become obtuse spontaneously.The atomic scale analysis of the morphology change demonstrates that the fracture is a process of eliminating the high energy structures,such as isolated atoms,twin boundary and surface kink.The surface of the fracture finally emerge many (111)facets with lower energies. Therefore the physical mechanism is attributed to the rule of energy minimization.
