首页|水环境下单晶铜纳米压痕缺陷演化与弹塑性变形行为研究

水环境下单晶铜纳米压痕缺陷演化与弹塑性变形行为研究

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从原子尺度探寻单晶铜在水介质参与下的纳米压痕实验过程中材料的塑性变形规律以及位错形核和缺陷演化过程.采用分子动力学方法,使用Lammps进行水环境下单晶铜纳米压痕模拟,观察压头在加载和卸载过程中的原子瞬态图像,最后得出其压痕过程的载荷-位移曲线,探究其弹塑性变形规律;通过Ovito可视化软件观察单晶铜在纳米压痕过程中HCP晶格类型的铜原子结构,分析单晶铜内部位错演化的4 个阶段,观察位错环的形核生长以及发射行为,探究不同位错环之间的形核演化异同,分析位错环的关联耦合效应.对比真空与水介质条件下二者的异同,结果表明:在加载过程中,水分子带走了单晶铜塑性变形的大部分能量,导致单晶铜的位错缺陷的种类和规模均会减小;在卸载过程中,由于水分子的残留,单晶铜表面更加粗糙,单晶铜亚表层的变形也更加严重.另外,不同位错环之间的演化过程较为相似,但压头下压深度越大,位错环的形核时间越滞后,位错规模越小.由此得出,在水环境中,材料的位错变形种类和规模都可以被有效地控制.
Study on Nanoindent Defect Evolution and Elastoplastic Deformation Behavior of Single Crystal Copper in Aqueous
The plastic deformation law of single crystal copper in the nanoinding experiment of aqueous medium and the evolution of dislocation nuclei and defects were explored from the atomic scale.Using molecular dynamics methods,lambs are used to simulate the nanoindentation of single crystal copper in aqueous environment,observe the atomic transient images of the indenter during loading and unloading,and finally obtain the load-displacement curve of the indentation process and explore the elastoplastic deformation law.Ovito visualization software is used to observe the structure of the copper atom of the HCP lattice type of single crystal copper in the nanoindentation process by,analyze the four stages of the evolution of the internal dislocation of single crystal copper,and observe the growth of the shaped nucleus and emission behavior of the dislocation ring.To explore the similarities and differences in the evolution of nucleation between different dislocation rings,and to analyze the associative coupling effect of dislocation rings,the similarities and differences between the two under vacuum and aqueous media conditions are compared.The results show that during the loading process,the water molecules take away most of the energy of the plastic deformation of single crystal copper,resulting in a decrease in the type and scale of dislocation defects of single crystal copper;in the unloading process,due to the residue of water molecules,the surface of single crystal copper is rougher,and the deformation of the subsurface of single crystal copper is more serious.In addition,the evolution process between different dislocation rings is similar,but the greater the depth of pressure down the indenter,the more the nucleus time lag of the dislocation ring,and the smaller the scale of dislocation.It is concluded that in the aquatic environment,the type and scale of dislocation deformation of the material can be effectively controlled.

water environmentmonocrystalline coppernano-indentationmolecular dynamics simulationdislocation

邱蓬勃、王全龙、武美萍、马成龙、缪小进、万光海

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江南大学 机械工程学院,江苏无锡 214122

水环境 单晶铜 纳米压痕 分子动力学仿真 位错

国家自然科学基金项目江苏省自然科学基金项目江苏省博士后科研计划

51705202BK2017019120212325

2024

机械科学与技术
西北工业大学

机械科学与技术

CSTPCD北大核心
影响因子:0.565
ISSN:1003-8728
年,卷(期):2024.43(10)