Next Article in Journal
Valuable Metal Recycling
Previous Article in Journal
Magnesium-β-Tricalcium Phosphate Composites as a Potential Orthopedic Implant: A Mechanical/Damping/Immersion Perspective
Article Menu
Issue 5 (May) cover image

Export Article

Open AccessArticle

Strengthening versus Softening of Nanotwinned Copper Depending on Prestress and Twin Spacing

School of Mechanical and Electrical Engineering, China University of Mining and Technology, Xuzhou 221116, China
College of Mechanics and Materials, Hohai University, Nanjing 210098, China
Key Laboratory of Advanced Structural Materials, Ministry of Education, Changchun University of Technology, Changchun 130012, China
State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China
Authors to whom correspondence should be addressed.
Metals 2018, 8(5), 344;
Received: 7 April 2018 / Revised: 6 May 2018 / Accepted: 8 May 2018 / Published: 11 May 2018
PDF [1465 KB, uploaded 11 May 2018]


This paper addressed the prestress- and twin spacing-dependent deformation as well as the hardening-to-softening transition in nanotwinned copper (nt-Cu) using molecular dynamics simulations. The results demonstrated that the hardening-to-softening transition always occurs at any prestress with decreasing twin spacing in nt-Cu compared with its single crystal counterpart, while it occurs at specific twin spacing with decreasing prestress. The hardening-to-softening transition induced by decreasing twin spacing or prestress is due to the same mechanism, i.e., transition in the initial plasticity mechanism from the activity of partial dislocation to twinning dislocation. Moreover, the indentation hardness increases with decreasing prestress, reaching its maximum, followed by decreases at smaller values for all nt-Cu. However, the critical prestress at the maximum indentation hardness significantly depends on twin spacing. Finally, a model was developed to explain this special deformation behavior. The present results could deepen our understanding of the deformation behavior of nt-Cu and provide a new paradigm for the design of this material under complex stress state. View Full-Text
Keywords: coherent twin boundary; molecular dynamics; dislocation; copper; nanoindentation coherent twin boundary; molecular dynamics; dislocation; copper; nanoindentation

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material


Share & Cite This Article

MDPI and ACS Style

Han, J.; Sun, J.; Han, Y.; Zhu, H.; Fang, L. Strengthening versus Softening of Nanotwinned Copper Depending on Prestress and Twin Spacing. Metals 2018, 8, 344.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Metals EISSN 2075-4701 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top