Materials can be strengthened by nanoscale stacking faults

¹ State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences Beijing 100190, China
² Department of Mechanical and Biomedical Engineering, City University of Hong Kong Kowloon, Hong Kong, China
³ School of Physics and Nuclear Energy Engineering, Beihang University - Beijing 100191, China
⁴ Department of Mechanical Engineering, Curtin University - Perth, WA 6845, Australia

^(a) meshen@cityu.edu.hk
^(b) C.Lu@curtin.edu.au

Received: 14 November 2014
Accepted: 29 April 2015

Abstract

In contrast to the strength of single crystals, stacking faults (SFs) are usually an unfavorable factor that weakens materials. Using molecular-dynamics simulations, we find that parallel-spaced SFs can dramatically enhance the strength of zinc-blende SiC nanorods, which is even beyond that of their single-crystal counterparts. Strengthening is achieved by restricting dislocation activities between nanoscale neighboring SFs and its overall upward trend is dominated by the volume fraction of SFs. The similar strengthening mechanism is also found in face-centered-cubic metals and their alloys. It is more promising than the traditional methods of decreasing nanoscale grains or twins due to the inverse Hall-Petch effect. This study sheds light on the structural design of nanomaterials with high strength.