Ultrafine-grained nickel refined by dislocation activities at intermediate strain rate impact: Deformation microstructure and mechanical properties

L. Farbaniec, A. Abdul-Latif, J. Gubicza, G. Dirras

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Abstract

This article presents an application of the impact-induced deformation in effective grain refinement in polycrystalline nickel. Ultrafine-grained microstructure was processed by means of Dynamic Plastic Deformation at room temperature using a falling impactor with a maximum impact velocity of 10 m s -1. The commercially pure (98.4 wt%) starting material was characterised by a coarsegrained (∼25 μm) microstructure. Electron backscattering diffraction and transmission electron microscopy studies showed that the initial equiaxed grains evolved into a laminar structure of submicron size narrow domains delineated by high-angle grain boundaries. The texture after deformation exhibits preferential orientations including a strong 220 fibre texture. The mechanical behaviour under quasi-static compression at room temperature and at a strain rate of 2 9 10 -3 s -1 was investigated in directions parallel and perpendicular to the impact axis. Stress-strain responses showed an increased yield strength (440-520 MPa) compared with the initial state (90 MPa). The strainhardening behaviour was found to strongly depend on the orientation of the compression axis.

Original languageEnglish
Pages (from-to)7932-7938
Number of pages7
JournalJournal of Materials Science
Volume47
Issue number22
DOIs
Publication statusPublished - Nov 1 2012

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ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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