Journal
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
Volume 397, Issue 1-2, Pages 330-337Publisher
ELSEVIER SCIENCE SA
DOI: 10.1016/j.msea.2005.03.001
Keywords
nickel; equal channel angular pressing; high-pressure torsion; microstructure; mechanical properties
Ask authors/readers for more resources
The structure and mechanical properties of Ni subjected to severe plastic deformation by means of equal channel angular pressing (ECAP) followed by cold rolling or high-pressure torsion were investigated. A material with uniform ultra-fine-grained (UFG) microstructure and mean grain size in the range from 100 to 600 urn, depending on the processing procedure, was obtained. Tensile tests at room temperature revealed ultimate tensile strength values in the range from 840 to 1270 MPa and an elongation to fracture in the range from 7 to 12% depending on the processing method. Annealing at 200 degrees C of the sample deformed by ECAP and cold rolling led to the best combination of strength and plasticity. The strength of the material was well above the level expected from the Hall-Petch rule. We explained this high strength by taking into account dislocations trapped at grain boundaries (TLDs). In ultra-fine-grained (LJFG) materials the specific surface of grain boundaries is high and therefore the TLDs density is high as well. The fracture and deformation relief indicate an important role of grain-boundary sliding and grain rotation as deformation mechanisms. The UFG high-strength Ni with relatively good ductility has a potential for applications in particular in microsystems, where the cross section of the material is in the micrometer range but still must cross a sufficient number of grains to look structurally uniform. (c) 2005 Published by Elsevier B.V.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available