TY - JOUR
T1 - Effect of annealing on percolating porosity in ultrafine-grained copper produced by equal channel angular pressing
AU - Ribbe, Jens
AU - Schmitz, Guido
AU - Gunderov, Dmitriy
AU - Estrin, Yuri
AU - Amouyal, Yaron
AU - Wilde, Gerhard
AU - Divinski, Sergiy V.
N1 - Funding Information:
This work was supported by Deutsche Forschungsgemeinschaft through research grants. One of the authors (Y.E.) would like to acknowledge profound and stimulating discussions of the stability of nanopores with Profs. G. Gottstein and L.S. Shvindlerman during his stay at RWTH Aachen, which was made possible through an Alexander von Humboldt Award. The authors are also grateful to Dr. Zuberova for her assistance with ECAP work. Useful exchanges of ideas with Profs. E. Rabkin, T. Lowe and R. Lapovok are gratefully acknowledged.
PY - 2013/8
Y1 - 2013/8
N2 - Percolating porosity as a specific type of deformation-induced was discovered in ultrafine-grained (UFG) Cu produced by equal channel angular pressing (Ribbe et al., Phys Rev Lett 2009;102:165501). The stability of this defect type against annealing under various conditions is investigated for UFG Cu of different purity levels. The porosity is found to withstand the annealing treatments up to 1073 K for several hours in purified Ar atmosphere, despite significant microstructure transformation. Annealing at 1313 K in Ar removes the percolating porosity, as do relatively short heat treatments at 427 K in a hydrogen-containing atmosphere. Quasi-hydrostatic pressure applied at moderate temperatures, e.g. 1 GPa at 423 K, eliminates the percolating porosity, too. A model of porosity evolution, which accounts for the experimental findings, is suggested.
AB - Percolating porosity as a specific type of deformation-induced was discovered in ultrafine-grained (UFG) Cu produced by equal channel angular pressing (Ribbe et al., Phys Rev Lett 2009;102:165501). The stability of this defect type against annealing under various conditions is investigated for UFG Cu of different purity levels. The porosity is found to withstand the annealing treatments up to 1073 K for several hours in purified Ar atmosphere, despite significant microstructure transformation. Annealing at 1313 K in Ar removes the percolating porosity, as do relatively short heat treatments at 427 K in a hydrogen-containing atmosphere. Quasi-hydrostatic pressure applied at moderate temperatures, e.g. 1 GPa at 423 K, eliminates the percolating porosity, too. A model of porosity evolution, which accounts for the experimental findings, is suggested.
KW - Defects
KW - Excess free volume
KW - Grain boundary diffusion
KW - Porosity
KW - Severe plastic deformation
UR - http://www.scopus.com/inward/record.url?scp=84882450885&partnerID=8YFLogxK
U2 - 10.1016/j.actamat.2013.05.036
DO - 10.1016/j.actamat.2013.05.036
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AN - SCOPUS:84882450885
SN - 1359-6454
VL - 61
SP - 5477
EP - 5486
JO - Acta Materialia
JF - Acta Materialia
IS - 14
ER -