TY - JOUR
T1 - Grain-boundary structure of oxygen-free high-conductivity (OFHC) copper subjected to severe plastic deformation and annealing
AU - Waryoba, D. R.
AU - Kalu, P. N.
AU - Crooks, R.
N1 - Funding Information:
The authors would like to thank NSF for their support through grants DMR-0351770 and DMR-0521392 for PREM and MRI, respectively. Finally, the Department of Energy (DOE) grant No. DE-FG02-04ER8390 is acknowledged.
PY - 2008/10/25
Y1 - 2008/10/25
N2 - The influence of grain-boundary structure on grain growth in copper subjected to severe plastic deformation has been studied using orientation imaging microscopy. The investigation was carried out on oxygen-free high-conductivity (OFHC) copper which was wire drawn to a true strain of about 4 and processed by equal-channel angular extrusion (ECAE) to 4 and 8 passes via "route Bc" (where the billet is rotated by 90° in the same direction between consecutive passes). The grain-boundary character distribution (GBCD) of the as-drawn wire was similar to that of ECAE-processed specimens, and both materials possessed a higher fraction of high-angle grain boundaries (HAGBs) than special coincidence-site lattice (CSL) boundaries. While the high fraction of HAGBs was retained in the annealed wires, they were transformed to CSL boundaries in the annealed ECAE-processed materials. In spite of an initially smaller grain size, when annealed at 750 °C for 1 h, the grain size of the 4-pass ECAE-processed material was larger than that of the wire drawn to a similar strain. This difference was attributed to a high density of high-mobility 35-50° 〈0 0 1〉 boundaries in the 4-pass ECAE materials. On the other hand, the presence of 50-60° 〈1 1 1 〉 pinning boundaries in the annealed 8-pass material accounted for the smaller grain size after recrystallization.
AB - The influence of grain-boundary structure on grain growth in copper subjected to severe plastic deformation has been studied using orientation imaging microscopy. The investigation was carried out on oxygen-free high-conductivity (OFHC) copper which was wire drawn to a true strain of about 4 and processed by equal-channel angular extrusion (ECAE) to 4 and 8 passes via "route Bc" (where the billet is rotated by 90° in the same direction between consecutive passes). The grain-boundary character distribution (GBCD) of the as-drawn wire was similar to that of ECAE-processed specimens, and both materials possessed a higher fraction of high-angle grain boundaries (HAGBs) than special coincidence-site lattice (CSL) boundaries. While the high fraction of HAGBs was retained in the annealed wires, they were transformed to CSL boundaries in the annealed ECAE-processed materials. In spite of an initially smaller grain size, when annealed at 750 °C for 1 h, the grain size of the 4-pass ECAE-processed material was larger than that of the wire drawn to a similar strain. This difference was attributed to a high density of high-mobility 35-50° 〈0 0 1〉 boundaries in the 4-pass ECAE materials. On the other hand, the presence of 50-60° 〈1 1 1 〉 pinning boundaries in the annealed 8-pass material accounted for the smaller grain size after recrystallization.
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U2 - 10.1016/j.msea.2007.09.083
DO - 10.1016/j.msea.2007.09.083
M3 - Article
AN - SCOPUS:49849104406
SN - 0921-5093
VL - 494
SP - 47
EP - 51
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
IS - 1-2
ER -