Dislocation density evolution during high pressure torsion of a nanocrystalline Ni-Fe alloy

Journal Article · Thu Jan 01 00:00:00 EST 2009 · Applied Physics Letters

OSTI ID:962322

Li, Hongqi ^[1]; Wang, Y B ^[2]; Ho, J C ^[2]; Cao, Y ^[2]; Liao, X Z ^[2]; Ringer, S P ^[2]; Zhu, Y T ^[2]; Zhao, Y H ^[2]; Lavernia, E J ^[2]

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1. Los Alamos National Laboratory
2. NON LANL

High-pressure torsion (HPT) induced dislocation density evolution in a nanocrystalline Ni-20wt.%Fe alloy was investigated using X-ray diffraction and transmission electron microscopy. Results suggest that the dislocation density evolution is different from that in coarse-grained materials. An HPT process first reduces the dislocation density within nanocrystalline grains and produces a large number of dislocations located at small-angle sub grain boundaries that are formed via grain rotation and coalescence. Continuing the deformation process eliminates the sub grain boundaries but significantly increases the dislocation density in grains. This phenomenon provides an explanation of the mechanical behavior of some nanostructured materials.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC52-06NA25396
• OSTI ID: 962322
• Report Number(s): LA-UR-09-01418; LA-UR-09-1418; APPLAB; TRN: US200919%%83
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALLOYS
COALESCENCE
DEFORMATION
DISLOCATIONS
GRAIN BOUNDARIES
ROTATION
TORSION
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION