Strenghening of Nickel deformed by high Pressure Torsion

Author(s)
H.W. Zhang, Xiaoxu Huang, Niels Hansen, Reinhard Pippan, Michael Zehetbauer
Abstract

The strength of a deformed metal depends on the content of high angle boundaries, low angle dislocation boundaries and the dislocations between the boundaries. High angle boundaries contribute by Hall-Petch strengthening, whereas for the low angle dislocation boundaries and dislocations between boundaries the strengthening is proportional to the square root of the dislocation density. Based on an assumption of additivity of these contributions, the flow stresses of metals deformed by cold rolling have been calculated successfully. In the present investigation pure Ni (99.9%) has been deformed by high pressure torsion (HPT) to von Mises strains of 0.9, 1.7, 8.7 and 12. The strength of the HPT Ni has been determined by Vickers microhardness (HV) measurements and the microstructural parameters have been determined by transmission electron microscope (TEM) in the longitudinal section. HPT has been compared with deformation by cold rolling and torsion based on the structural evolution with strain and the stress-structure relationship. Based on an assumption of a linear additivity of boundary strengthening and dislocation strengthening, good agreement has been found between the calculated and the experimental flow stress.

Organisation(s)
Physics of Nanostructured Materials
External organisation(s)
Technical University of Denmark (DTU), Riso National Laboratory, Österreichische Akademie der Wissenschaften (ÖAW)
Journal
Materials Science Forum
Volume
584-586
Pages
417-421
No. of pages
5
ISSN
0255-5476
DOI
https://doi.org/10.4028/www.scientific.net/MSF.584-586.417
Publication date
2008
Peer reviewed
Yes
Austrian Fields of Science 2012
103023 Polymer physics, 210006 Nanotechnology, 103018 Materials physics
Portal url
https://ucris.univie.ac.at/portal/en/publications/strenghening-of-nickel-deformed-by-high-pressure-torsion(805a189f-3250-4470-96b4-bd11b14ac7d9).html