应变速率对纳米杆断裂分布与初始滑移分布相关性的影响  

The influence of strain rate on the correlation between the initial slip distribution and the fracture distribution in the nanorods

作　　者：宗文 赵健伟[2] 马汉杰[3] ZONG Wen;ZHAO Jan-wei;Ma Han-jie(School of Information Science and Engineering,Zhejiang Sci-Tech University,Hangzhou 310000,China;College of Material and Textile Engineering,Jiaxing University,Jiaxing 314001,China;College of Computer Science and Technology(School of Artificial Intelligence),Zhejiang Sci-Tech University,Hangzhou 310000,China)

机构地区：[1]浙江理工大学信息科学与工程学院,浙江杭州310000 [2]嘉兴学院材料与纺织工程学院,浙江嘉兴314001 [3]浙江理工大学计算机科学与技术学院(人工智能学院),浙江杭州310000

出　　处：《化学研究与应用》2024年第5期1067-1077,共11页Chemical Research and Application

基　　金：国家自然科学基金项目(51861145202)资助。

摘　　要：金属纳米材料具有独特的物理和化学性质,因此被广泛应用于各种领域的器件制造中。然而,纳米尺度下材料性能表现的外在响应具有很大的不确定性,应变速率是一个重要的影响因素。为了深入探究金属纳米材料机械力学性能对应变速率的响应以及纳米杆断裂失效与初始微观结构之间的关系,本文构建了金属纳米杆模型,并通过分子动力学模拟研究了单晶Cu纳米杆在不同应变速率下拉伸的形变过程。利用基于密度的噪声应用空间聚类(DBSCAN)机器学习算法,获得了初始微观结构缺陷的位置。在对比了每个速率300个样本,共计2700个样本后,得出纳米杆断裂位置与初始滑移分布的相关性特征。结果表明,当应变速率高于0.08%ps^(-1)时,初始滑移主要分布在纳米杆两端,但断裂位置分布却集中在中间。随着应变速率的降低,初始滑移分布则愈发均匀,断裂位置分布则更趋向于两端。而纳米杆的断裂强度和塑性形变能力则随着应变速率的提高而提高。这一研究结果可以为金属纳米材料的设计和制造提供有价值的参考。Metallic nanomaterials possess unique physical and chemical properties,making them widely employed in device manufacturing across various fields.However,at the nanoscale,the external responses of material performance exhibit significant uncertainties,with strain rate being a crucial influencing factor.In order to delve deeper into the mechanical properties of metallic nanomaterials in response to strain rates and the relationship between nanowire fracture failure and initial microstructures,this paper constructs a model of metallic nanowires and conducts molecular dynamics simulations on the tensile deformation process of single-crystal Cu nanowires at different strain rates.Using a density-based spatial clustering of applications with noise(DBSCAN)machine learning algorithm,we obtain the positions of initial microstructural defects.After comparing 300 samples at each rate,totaling 2700 samples,we draw conclusions regarding the correlation features between nanowire fracture locations and initial slip distribution.The results indicate that when the strain rate exceeds 0.08%ps^(-1),initial slip predominantly occurs at both ends of the nanowire,yet fracture locations concentrate in the middle.As the strain rate decreases,the initial slip distribution becomes more uniform,and fracture locations tend to shift towards both ends.Furthermore,the fracture strength and plastic deformation capability of the nanowire increase with higher strain rates.These research findings offer valuable insights for the design and manufacturing of metallic nanomaterials.

关 键 词：分子动力学 应变速率 DBSCAN 初始滑移 断裂位置 

分 类 号：O641[理学—物理化学]