Mechanical properties and microstructural evolutions at high strain rates of electrodeposited nickel

H. Couque, A. Ouarem, G. Dirras, J. Gubicza

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The mechanical and microstructural characteristics of high purity nickel processed by electrodeposition tested in compression up to a dynamic strain rate of 1.5 x 105 s-1 using a direct impact Hopkinson pressure bar technique have been analyzed. The nickel exhibits thermal activated strain rate sensitivity up to about 103 s-1. At higher rates, a sharp increase of the strength is observed related to dislocation drag effects known as the viscous regime. This strain rate dependence is best reproduced through a modified Johnson-Cook constitutive model uncoupling the strain rate dependence and the temperature dependence. Microstructure analyses reveal an increase of the average grain size with the strain rate increasing up to about 1 x 104 s-1 and are related to the reduction of amount of twins. The twin structure generated in the early shock stage of the loading evolves through dislocation interactions during the plastic deformation occurring under unshocked conditions. At a higher strain rate of 1.5 x 10 5 s-1, the grain size is decreasing to the value similar to initial state. At this strain rate, high dislocation density along with the temperature increase due to plastic deformation might favour dynamic recrystallization thus resulting in a decrease of the grain size.

Original languageEnglish
Title of host publication65th ABM International Congress, 18th IFHTSE Congress and 1st TMS/ABM International Materials Congress 2010
Pages5248-5256
Number of pages9
Publication statusPublished - Dec 1 2010
Event65th ABM International Congress, 18th IFHTSE Congress and 1st TMS/ABM International Materials Congress 2010 - Rio de Janeiro, Brazil
Duration: Jul 26 2010Jul 30 2010

Publication series

Name65th ABM International Congress, 18th IFHTSE Congress and 1st TMS/ABM International Materials Congress 2010
Volume6

Other

Other65th ABM International Congress, 18th IFHTSE Congress and 1st TMS/ABM International Materials Congress 2010
CountryBrazil
CityRio de Janeiro
Period7/26/107/30/10

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Keywords

  • High strain rate
  • Nickel
  • Recrystallization

ASJC Scopus subject areas

  • Mechanics of Materials

Cite this

Couque, H., Ouarem, A., Dirras, G., & Gubicza, J. (2010). Mechanical properties and microstructural evolutions at high strain rates of electrodeposited nickel. In 65th ABM International Congress, 18th IFHTSE Congress and 1st TMS/ABM International Materials Congress 2010 (pp. 5248-5256). (65th ABM International Congress, 18th IFHTSE Congress and 1st TMS/ABM International Materials Congress 2010; Vol. 6).