Cross-over of the Plasticity Mechanism in Nanocrystalline Cu
YUE Yong-Hai1, WANG Li-Hua1, ZHANG Ze1,2, HAN Xiao-Dong1**
1Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124 2 Department of Materials Science, State Key Lab of Si Materials, Zhejiang University, Hangzhou 310027
Cross-over of the Plasticity Mechanism in Nanocrystalline Cu
YUE Yong-Hai1, WANG Li-Hua1, ZHANG Ze1,2, HAN Xiao-Dong1**
1Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124 2 Department of Materials Science, State Key Lab of Si Materials, Zhejiang University, Hangzhou 310027
Abstract：Via in situ uniaxial tensile tests in a high-resolution transmission electron microscope, we directly observed a cross-over of plastic deformation mechanisms in a nanocrystalline (nc) Cu thin film containing nano-twin lamellae. For a certain twin lamellae length, the twin lamellae with a larger thickness emit dislocations inclined (Schmidt-factor dislocations, i.e., S-dislocations) toward the twin boundaries. Upon decreasing the twin lamellae thickness to a critical value, such as approximately 15 nm, the plasticity switches toward emission of twinning partial dislocations (T-dislocations) parallel to the twin planes that cause migration of the twin boundaries. The critical twin thickness value also depends on the length of the twin. These results provide direct evidence for the strengthening and softening mechanisms in nano-twinning structured metals.
YUE Yong-Hai, WANG Li-Hua, ZHANG Ze, HAN Xiao-Dong. Cross-over of the Plasticity Mechanism in Nanocrystalline Cu[J]. 中国物理快报, 2012, 29(6): 66201-066201.
YUE Yong-Hai, WANG Li-Hua, ZHANG Ze, HAN Xiao-Dong. Cross-over of the Plasticity Mechanism in Nanocrystalline Cu. Chin. Phys. Lett., 2012, 29(6): 66201-066201.
2012, Vol. 29 
