Microstructure and mechanical behavior of UFG copper processed by ECAP following different processing regimes


PÜRÇEK G. , Saray O., Nagimov M. I. , Nazarov A. A. , Safarov I. M. , Danilenko V. N. , ...More

PHILOSOPHICAL MAGAZINE, vol.92, no.6, pp.690-704, 2012 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 92 Issue: 6
  • Publication Date: 2012
  • Doi Number: 10.1080/14786435.2011.634842
  • Title of Journal : PHILOSOPHICAL MAGAZINE
  • Page Numbers: pp.690-704

Abstract

Commercially pure (99.9%) copper was severe plastically deformed by equal-channel angular pressing (ECAP) following route-Bc in three different processing regimes in order to obtain ultrafine-grained (UFG) microstructures leading to improved mechanical properties. In regime-1, the billets were processed at room temperature up to eight passes. The billets were processed at 200 degrees C up to eight passes in regime-2. Regime-3 is a hybrid regime by which the billets were deformed at 200 degrees C up to four passes first, and these billets were then processed at room temperature for one, two and four passes. In all regimes, the ECAP processing results in a refinement of the conventionally grained (CG) initial microstructure of copper down to sub-micron level leading to a great improvement in the strength as compared to CG copper. Among the regimes applied, regime-3 was found to be the best regime for improvement in strength along with adequate ductility. The samples showed more than eight times increases in yield strength after processing in regime-3 for 4 + 4 passes, from 47 MPa for CG copper to about 408 MPa for the UFG sample. Such improvement in strength was accompanied by a 16.9% total elongation and 6% uniform elongation. The processing in regime-2 resulted in the best elongation to failure of about 22% after eight passes, but it gave the lowest strength values among others.