Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1579556 | Materials Science and Engineering: A | 2010 | 8 Pages |
Abstract
High purity electrolytic nickel (99.99%) samples deformed dynamically in compression using a direct impact Hopkison pressure bar test at the velocities of 10.9, 28.2 and 70.6 m sâ1 were investigated. The dislocation density increased with increasing the impact velocity up to 28.2 m sâ1 resulting in an increase of nanohardness and quasi-static compressive flow stress. At the same time, a decrease of the fraction of Σ3 coincident site lattice boundaries was observed for the benefit of Σ1 low angle grain boundaries having misorientations lower than 15°. Increasing the velocity to 70.6 m sâ1 led to a decrease of the dislocation density, in parallel with the regeneration of Σ3 boundaries. As a consequence, the nanohardness decreased to a similar value as in the initial state. These observations suggest possible dynamic recovery/recrystallization that might have occurred at the highest impact velocity.
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Authors
G. Dirras, H. Couque, J. Gubicza, A. Ouarem, T. Chauveau, P. Jenei,