TY - JOUR
T1 - Application of equal-channel angular pressing to Cu-Co alloy with ferromagnetic precipitates
AU - Fujita, Takeshi
AU - Nishimura, Shunichi
AU - Fujinami, Takayoshi
AU - Kaneko, Kenji
AU - Horita, Zenji
AU - Smith, David J.
N1 - Funding Information:
This study was supported by the Japan Society for the Promotion of Science for the award of Postdoctoral Fellowships for Research Abroad. We acknowledge Professor M.R. McCartney at Arizona State University for helpful advice and we acknowledge use of facilities in the John M. Cowley Center for High Resolution Electron Microscopy. We used a JEM-2010FEF analytical electron microscope in the HVEM Laboratory of Kyushu University. Our thanks are also to Prof. Syo Matsumura of Kyushu University for providing the X-ray spectral-imaging system installed through the Special Coordination Funds for Promoting Science and Technology on “Nanohetero Metallic Materials” provided by the Ministry of Education, Culture, Sports, Science and Technology.
PY - 2006/2/15
Y1 - 2006/2/15
N2 - Experiments were conducted to evaluate the influence of equal-channel angular pressing (ECAP) on the magnetic properties of a Cu-1.8 wt.% Co alloy containing 0.2 wt.% Cr which forms ferromagnetic Co-rich precipitates in the Cu matrix after aging treatment. Coherent face-centered-cubic precipitates were formed by isothermal aging at 873 and 1073 K for 259 ks. The two different aging temperatures gave precipitates of different sizes, which were expected to show either single-domain or multidomain structure. In the case of small precipitates, one pass of ECAP was effective to improve coercivity, but further pressings tended to decrease coercivity and saturation magnetization due to random orientation and dissolution of the precipitates. In the case of large precipitates, shape change to increase coercivity is difficult. Saturation magnetization was increased by the demagnetizing effect of the precipitates. Electron holography provided the quantitative magnetization measurements for rounded cubic and elongated Co precipitates, indicating the increased in-plane magnetization of the elongated precipitate due to the demagnetizing effect as a result of deformation.
AB - Experiments were conducted to evaluate the influence of equal-channel angular pressing (ECAP) on the magnetic properties of a Cu-1.8 wt.% Co alloy containing 0.2 wt.% Cr which forms ferromagnetic Co-rich precipitates in the Cu matrix after aging treatment. Coherent face-centered-cubic precipitates were formed by isothermal aging at 873 and 1073 K for 259 ks. The two different aging temperatures gave precipitates of different sizes, which were expected to show either single-domain or multidomain structure. In the case of small precipitates, one pass of ECAP was effective to improve coercivity, but further pressings tended to decrease coercivity and saturation magnetization due to random orientation and dissolution of the precipitates. In the case of large precipitates, shape change to increase coercivity is difficult. Saturation magnetization was increased by the demagnetizing effect of the precipitates. Electron holography provided the quantitative magnetization measurements for rounded cubic and elongated Co precipitates, indicating the increased in-plane magnetization of the elongated precipitate due to the demagnetizing effect as a result of deformation.
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U2 - 10.1016/j.msea.2005.11.008
DO - 10.1016/j.msea.2005.11.008
M3 - Article
AN - SCOPUS:31044437826
SN - 0921-5093
VL - 417
SP - 149
EP - 157
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 -