TY - JOUR
T1 - Development of new Co-Cr-W-based biomedical alloys
T2 - Effects of microalloying and thermomechanical processing on microstructures and mechanical properties
AU - Yamanaka, Kenta
AU - Mori, Manami
AU - Kuramoto, Koji
AU - Chiba, Akihiko
N1 - Funding Information:
The authors would like to thank Isamu Yoshii, Kimio Wako, Fumiya Sato, Shun Ito, and Issei Narita, IMR, Tohoku University, for contributing sample preparation, TEM observations and EPMA analysis. 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 Strategy Support Program, NICHe, Tohoku University, and the Regional Innovation Cluster Program from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
PY - 2014/3
Y1 - 2014/3
N2 - The application of computer-aided design and computer-aided manufacturing (CAD/CAM) to dentistry has recently attracted considerable attention as a new technique for designing and fabricating custom-made dental implants. Here, a strategy combining microalloying with thermomechanical processing are described to design new Co-28Cr-9W-1Si-C (wt%) alloys for use as disks in the CAD/CAM-based machining of dental restorations. On the basis of our thermodynamic calculations, Si and C were selected as alloying elements that cause the brittle σ phase precipitates to be replaced with the plastically deformable Laves phase and thus enhance the alloy's hot workability. The effect of thermomechanical processing on the microstructure evolution and mechanical properties of the designed alloys was preliminarily studied by performing multipass hot rolling. The hot-rolled alloys exhibited refined grains (mean grain sizes ~10. μm) and high densities of lattice defects (dislocations, stacking faults, etc.), both of which were obtained as a result of dynamic recrystallization during hot rolling. It was found experimentally that this approach permits the alloy strength and ductility to be increased simultaneously. The static recrystallization occurring during cooling after deformation also modifies the mechanical properties of the alloys. Carbon doping (<0.1. wt%) increases the amount of precipitates and further improves both the strength and elongation-to-failure of the hot-rolled alloys. Thus, the newly developed alloys have advantageous characteristics in terms of both fabrication and mechanical properties. In addition, the outstanding tensile ductility of the developed alloys could make them suitable for vascular stents.
AB - The application of computer-aided design and computer-aided manufacturing (CAD/CAM) to dentistry has recently attracted considerable attention as a new technique for designing and fabricating custom-made dental implants. Here, a strategy combining microalloying with thermomechanical processing are described to design new Co-28Cr-9W-1Si-C (wt%) alloys for use as disks in the CAD/CAM-based machining of dental restorations. On the basis of our thermodynamic calculations, Si and C were selected as alloying elements that cause the brittle σ phase precipitates to be replaced with the plastically deformable Laves phase and thus enhance the alloy's hot workability. The effect of thermomechanical processing on the microstructure evolution and mechanical properties of the designed alloys was preliminarily studied by performing multipass hot rolling. The hot-rolled alloys exhibited refined grains (mean grain sizes ~10. μm) and high densities of lattice defects (dislocations, stacking faults, etc.), both of which were obtained as a result of dynamic recrystallization during hot rolling. It was found experimentally that this approach permits the alloy strength and ductility to be increased simultaneously. The static recrystallization occurring during cooling after deformation also modifies the mechanical properties of the alloys. Carbon doping (<0.1. wt%) increases the amount of precipitates and further improves both the strength and elongation-to-failure of the hot-rolled alloys. Thus, the newly developed alloys have advantageous characteristics in terms of both fabrication and mechanical properties. In addition, the outstanding tensile ductility of the developed alloys could make them suitable for vascular stents.
KW - Biomedical Co-Cr-W alloy
KW - Mechanical properties
KW - Microstructure
KW - Precipitates
KW - Thermomechanical processing
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U2 - 10.1016/j.matdes.2013.10.052
DO - 10.1016/j.matdes.2013.10.052
M3 - Article
AN - SCOPUS:84888059245
VL - 55
SP - 987
EP - 998
JO - International Journal of Materials in Engineering Applications
JF - International Journal of Materials in Engineering Applications
SN - 0264-1275
ER -