DYMAT 2009
Volume 2, 2009
DYMAT 2009 - 9th International Conference on the Mechanical and Physical Behaviour of Materials under Dynamic Loading
Page(s) 1195 - 1200
Section Micro-Structural Effects
Published online 15 September 2009
DYMAT 2009 (2009) 1195-1200
DOI: 10.1051/dymat/2009168

Mechanical behavior of ultrafine grained OFHC Cu at high strain rates

L.J. Park1, H.W. Kim1, C.S. Lee2 and K.-T. Park3

1  Agency for Defense Development, PO Box 35-42, 305-600 Daejeon, Korea
2  Dept. of Mater. Sci. Eng., POSTECH, 790-784 Pohang, Korea
3  Division of Advanced Mater. Sci. & Eng., Hanbat Nat'l Univ., 305-719 Daejeon, Korea

Published online: 15 September 2009

The quasi-static and dynamic mechanical behaviors of ultrafine grained (UFG) oxygen free high conductivity copper (OFHC Cu) were compared with those of its coarse grained counterpart. A special focus was made on examining the effect of a UFG structure on the mechanical response under quasi-static and dynamic loading. For this purpose, OFHC Cu having the lamellar and equiaxed UFG structure was prepared by equal channel angular pressing of route A and Bc, respectively. The quasi-static and dynamic tests were conducted using a universal testing machine and the split Hopkins pressure bar tester in the strain rate range of 10−3 ~ 5000 s−1. The UFG sample exhibited much enhanced yield stress over the coarse grained sample but showed a ductility loss due to the lack of strain hardenability under the quasi-static loading condition. In addition, shear failure occurred in the UFG samples even under quasi-static tensile mode. The deformation resistance of the equiaxed UFG sample against dynamic loading was found to be similar to that of the transverse lamellar UFG sample (i.e. impact loading perpendicular to the longitudinal lamellar direction), but that of the longitudinal lamellar UFG sample (i.e. impact loading parallel to the longitudinal lamellar direction) was inferior. In addition, the effect of ECAP pass number, which greatly affects the nature of the UFG structure, on the deformation resistance was briefly discussed.

© EDP Sciences 2009