首页|Cu Σ15晶界结构低能化转变的微观机制研究

Cu Σ15晶界结构低能化转变的微观机制研究

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采用分子动力学模拟方法对Cu Σ15晶界的结构转变过程进行了系统研究,发现在单轴拉伸作用下Cu Σ15[(11)2](5(1)2)晶界会向Σ11[(11)2]((1)31)晶界发生低能化结构转变.位错演化和原子运动轨迹分析表明,该结构转变过程主要在两种肖克莱不全位错b1=1/6[(21)1]和b3=1/6[(121)]的共同作用下完成.首先b1位错从与Σ15晶界六边形结构单元的5和6号原子处形核并发射,此后其在{1 11}面上滑移导致内禀型堆垛层错的形成;b3位错随后在与b1同样位置形核并发射,引起{1(1)1}面上原子二次重排,从而导致堆垛层错消失.在上述位错作用下,Cu Σ15晶界中原本组成六边形结构单元的5和6号原子脱离晶界区域,沿{1(1)1｝面进入晶粒内而变为体相原子,剩余4个原子则重新排列形成四边形结构单元;Cu Σ15晶界由此逐步完成向Σ11晶界的结构低能化转变.
Study on microscopic mechanism of low-energy transition of Cu Σ15 grain boundary structure
The molecular dynamics simulation method was employed to symmetrically investigate the structural transformation process of Cu Σ15 grain boundary(GB).It is found that the Cu Σ15[(11)2](5(1)2)GB undergoes an energy-lowering structural transformation to the Σ11[(11)2]((1)3 1)GB under uniaxial tension action.The analysis of dislocation evolution and atomic movement trajectory indi-cates that the structural transformation process is mainly completed under the joint action of two Shockley partial dislocations b1=1/6[(21)1]and b3=1/6[(121)].Firstly,the b1 dislocation nucleates and emits from the atom 5 and atom 6 of the hexagonal structure unit of Σ15 GB.Then,it slips on the {1(1)1} plane,leading to the formation of intrinsic stacking faults.The b3 dislocation then nucleates and emits at the same position with b1,causing a rearrangement of atoms on { 1(1)1} plane and the disappearance of the stacking faults.With the above-mentioned dislocation action,the atom 5 and atom 6,which originally formed the hexagonal structural unit of the Cu Σ15 GB,break away from the original GB region and enter into grain interior along the {1(1)1} plane,these two atoms thus turn into bulk atoms,while the remaining four atoms rearrange and then form the quadrilateral structural unit,in which way the energy-lowering structural trans-formation from Cu Σ15 GB to Σ11 GB gradually completes.

Σ15 symmetric tilt grain boundaryGB structural transformationgrain boundary relaxationuniaxial tensilemolecular dy-namics simulation

薛红涛、张志军、张其虎、汤富领、任军强、卢学峰、李俊琛

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兰州理工大学材料科学与工程学院省部共建有色金属先进加工与再利用国家重点实验室,甘肃兰州 730050

Σ15对称倾斜晶界 晶界结构转变 晶界弛豫 单轴拉伸 分子动力学模拟

国家自然科学基金资助项目中央引导地方科技发展资金资助项目甘肃省科技重大专项沈阳材料科学国家(联合)实验室-有色金属加工与再利用国家重点实验室联合基金资助项目有色金属加工与再利用国家重点实验室优秀青年人才培养计划项目

1220421023ZYQB30022ZD6GA00818LHPY0032018001

2024

10.3969/j.issn.1007-2012.2024.06.019

塑性工程学报
中国机械工程学会

塑性工程学报

CSTPCD北大核心
影响因子：0.46
ISSN：1007-2012
年,卷(期)：2024.31(6)
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