Deformation Twinning in Nanocrystalline Ni during Cryogenic Rolling
FENG Xiu-Yan1, CHENG Zhi-Ying2, ZHOU Jia1, WU Xiao-Lei1, WANG Zi-Qiang1, HONG You-Shi1
1State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080
2Department of Materials Science Engineering, Tsinghua University, Beijing 100084
Deformation Twinning in Nanocrystalline Ni during Cryogenic Rolling
1State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080
2Department of Materials Science Engineering, Tsinghua University, Beijing 100084
Abstract： Deformation twinning is evidenced by transmission electron microscopy examinations in electrodeposited nanocrystalline (nc) Ni with mean grain size 25nm upon cryogenic rolling. Two twinning mechanisms are confirmed to operate in nc grains, i.e. heterogeneous formation via emission of partial dislocations from the grain boundary and homogeneous nucleation through dynamic overlapping of stacking faults, with the former being determined as the most proficient. Deformation twinning in nc Ni may be well interpreted in terms of molecular dynamics simulation based on generalized planar fault energy curves.
2006, Vol. 23 
