TY - JOUR
T1 - Effects of aging temperature on electrical conductivity and hardness of Cu-3 at. pct Ti alloy aged in a hydrogen atmosphere
AU - Semboshi, Satoshi
AU - Nishida, Tomoya
AU - Numakura, Hiroshi
AU - Al-Kassab, Tala'At
AU - Kirchheim, Reiner
N1 - Funding Information:
The authors are grateful to Professors S. Hanada, N. Masahashi, and T.J. Konno, Institute for Materials Research, Tohoku University, and Professor A. Pundt, Institute for Material Physics, University of Göttingen, for useful discussion and comments. The authors also thank Messrs R. Thomas, S. Wagner, R. Gemma, C. Izawa, and H.H. Uchida, Institute for Material Physics, University of Göttingen, for assisting in sample preparation and APT analysis. This work was partly performed under the dispatch program of Osaka Prefecture University and under the inter-university co-operative research program of the Institute for Materials Research of Tohoku University. The financial support provided by the Inamori Foundation, Japan Research Institute for Advanced Copper-based Materials and Technologies, New Energy and Industrial Technology Development Organization (NEDO), and Japan Science and Technology Agency (JST) is gratefully acknowledged.
PY - 2011/8
Y1 - 2011/8
N2 - To improve the balance of the electrical conductivity and mechanical strength for dilute Cu-Ti alloys by aging in a hydrogen atmosphere, the influence of aging temperature ranging from 673 K to 773 K (400 °C to 500 °C) on the properties of Cu-3 at. pct Ti alloy was studied. The Vickers hardness increases steadily with aging time and starts to fall at 3 hours at 773 K (500 °C), 10 hours at 723 K (450 °C), or over 620 hours at 673 K (400 °C), which is the same as the case of conventional aging in vacuum. The maximum hardness increases from 220 to 236 with the decrease of aging temperature, which is slightly lower than aging at the same temperature in vacuum. The electrical conductivity at the maximum hardness also increases from 18 to 32 pct of pure copper with the decrease of the temperature, which is enhanced by a factor of 1.3 to 1.5 in comparison to aging in vacuum. Thus, aging at 673 K (400 °C) in a hydrogen atmosphere renders fairly good balance of strength and conductivity, although it takes nearly a month to achieve. The microstructural changes during aging were examined by transmission electron microscopy (TEM) and atom-probe tomography (APT), it was confirmed that precipitation of the Cu4Ti phase occurs first and then particles of TiH2 form as the third phase, thereby efficiently removing the Ti solutes in the matrix.
AB - To improve the balance of the electrical conductivity and mechanical strength for dilute Cu-Ti alloys by aging in a hydrogen atmosphere, the influence of aging temperature ranging from 673 K to 773 K (400 °C to 500 °C) on the properties of Cu-3 at. pct Ti alloy was studied. The Vickers hardness increases steadily with aging time and starts to fall at 3 hours at 773 K (500 °C), 10 hours at 723 K (450 °C), or over 620 hours at 673 K (400 °C), which is the same as the case of conventional aging in vacuum. The maximum hardness increases from 220 to 236 with the decrease of aging temperature, which is slightly lower than aging at the same temperature in vacuum. The electrical conductivity at the maximum hardness also increases from 18 to 32 pct of pure copper with the decrease of the temperature, which is enhanced by a factor of 1.3 to 1.5 in comparison to aging in vacuum. Thus, aging at 673 K (400 °C) in a hydrogen atmosphere renders fairly good balance of strength and conductivity, although it takes nearly a month to achieve. The microstructural changes during aging were examined by transmission electron microscopy (TEM) and atom-probe tomography (APT), it was confirmed that precipitation of the Cu4Ti phase occurs first and then particles of TiH2 form as the third phase, thereby efficiently removing the Ti solutes in the matrix.
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U2 - 10.1007/s11661-011-0637-8
DO - 10.1007/s11661-011-0637-8
M3 - Article
AN - SCOPUS:79959542546
SN - 1073-5623
VL - 42
SP - 2136
EP - 2143
JO - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
JF - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
IS - 8
ER -