TY - JOUR
T1 - Effects of nitrogen on microstructural evolution of biomedical Co-Cr-W alloys during hot deformation and subsequent cooling
AU - Yamanaka, Kenta
AU - Mori, Manami
AU - Chiba, Akihiko
N1 - Funding Information:
The authors would like to thank Koji Kuramoto and Shun Ito for contributing to the sample preparation and TEM observations. This research was financially supported by the Grant-in-Aid for JSPS Fellows, the Global COE Program “Materials Integration (International Center of Education and Research), Tohoku University”, the Regional Innovation Cluster Program from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT), Japan, and the Supporting Industry Program from the Ministry of Economy, Trade, and Industry (METI), Japan.
PY - 2014/5
Y1 - 2014/5
N2 - The present study investigated how nitrogen affected the high-temperature deformation and microstructural evolution of biomedical Ni-free Co-Cr-W alloys during hot deformation. Hot compression tests of undoped and N-doped Co-28Cr-9W-1Si-0.05C (mass%) alloys were performed at deformation temperatures ranging from 1323 to 1473K at strain rates of 10-3 to 10s-1. The microstructures, which were subjected to a true strain of 0.92 (60% in compression), were characterized using electron backscatter diffraction (EBSD) analysis and transmission electron microscopy (TEM). Dynamic recrystallization (DRX) was found to occur in both alloys during hot deformation. The grain size (d) decreased considerably with an increase in the Zener-Hollomon (Z) parameter. Although adding nitrogen to the alloys barely affected dynamic-recrystallization-induced grain refinement, it increased the magnitude of the flow stress and delayed static recrystallization during post-deformation cooling. Consequently, the N-doped alloy contained bulk nanostructures whose average grain size was 0.9μm.
AB - The present study investigated how nitrogen affected the high-temperature deformation and microstructural evolution of biomedical Ni-free Co-Cr-W alloys during hot deformation. Hot compression tests of undoped and N-doped Co-28Cr-9W-1Si-0.05C (mass%) alloys were performed at deformation temperatures ranging from 1323 to 1473K at strain rates of 10-3 to 10s-1. The microstructures, which were subjected to a true strain of 0.92 (60% in compression), were characterized using electron backscatter diffraction (EBSD) analysis and transmission electron microscopy (TEM). Dynamic recrystallization (DRX) was found to occur in both alloys during hot deformation. The grain size (d) decreased considerably with an increase in the Zener-Hollomon (Z) parameter. Although adding nitrogen to the alloys barely affected dynamic-recrystallization-induced grain refinement, it increased the magnitude of the flow stress and delayed static recrystallization during post-deformation cooling. Consequently, the N-doped alloy contained bulk nanostructures whose average grain size was 0.9μm.
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U2 - 10.1016/j.matdes.2013.12.080
DO - 10.1016/j.matdes.2013.12.080
M3 - Article
AN - SCOPUS:84892990561
VL - 57
SP - 421
EP - 425
JO - International Journal of Materials in Engineering Applications
JF - International Journal of Materials in Engineering Applications
SN - 0264-1275
ER -