Nano Express

Nanoscale Research Letters

, Volume 5, Issue 4, pp 692-700

Open Access This content is freely available online to anyone, anywhere at any time.

Multiscale Simulation of Indentation, Retraction and Fracture Processes of Nanocontact

  • Jifa MeiAffiliated withDepartment of Mechanics and Engineering Science, Fudan University
  • , Junwan LiAffiliated withDepartment of Mechanics and Engineering Science, Fudan University
  • , Yushan NiAffiliated withDepartment of Mechanics and Engineering Science, Fudan University Email author 
  • , Huatao WangAffiliated withDepartment of Mechanics and Engineering Science, Fudan University

Abstract

The process of nanocontact including indentation and retraction between a large Ni tip and a Cu substrate is investigated using quasicontinuum (QC) method. The multiscale model reveals that significant plastic deformation occurs during the process of nanocontact between Ni tip and Cu substrate. Plastic deformation is observed in an area as large as 20 nm wide and 10 nm thick beneath Ni tip during the indentation and retraction. Also, plastic deformation at a deep position in the Cu substrate does not disappear after the neck failure. The analysis of generalized planar fault energy curve shows that there is a strong tendency for deformation twinning in Cu substrate. However, deformation twinning will be retarded during indentation due to the high stress intensity caused by stepped surface of Ni tip. The abrupt drop of load curve during tip retraction is attributed to the two different fracture mechanisms. One is atomic rearrangement near the interface of Ni tip and Cu substrate at the initial stage of neck fracture, the other is shear behavior of adjacent {111} planes at the necking point. A comparison of the critical load and critical contact radius for neck fracture is also made between theoretical values and our numerical results.

Keywords

Multiscale simulation Quasicontinuum method Nanocontact Neck fracture