TY - GEN
T1 - Microstructural analysis of biomedical Co-Cr-Mo alloy subjected to high-pressure torsion processing
AU - Isik, Murat
AU - Niinomi, Mitsuo
AU - Cho, Ken
AU - Nakai, Masaaki
AU - Hieda, Junko
AU - Yilmazer, Hakan
AU - Horita, Zenji
AU - Narushima, Takayuki
PY - 2014
Y1 - 2014
N2 - The effect of high-pressure torsion (HPT) processing on the microstructure and Vickers hardness of Co-Cr-Mo (CCM) alloys were investigated in this study. The microstructure of initial CCM alloy contains equiaxed grains with a grain diameter of approximately 50 μm and twins. The clear grain boundaries of equiaxed grains and twins disappear after HPT processing at a rotation number, N, of 10. The phase maps of initial CCM alloy and CCM alloy subjected to HPT processing at N = 5 measured by electron backscatter diffraction exhibit that the ratio of γ phase decreases from 93.5% to 34.1% and the ratio of ε phase increases from 6.5% to 65.9% by applying HPT processing. These results indicate that the ε phase is formed by high-strain, which is induced by the HPT processing. The Vickers hardness values on the surfaces of the CCM alloys subjected to HPT processing at N = 1, 5, and 10 increase with increasing the equivalent strain, εeq. These results suggest that an increase of Vickers hardness is correlated to an increase of the ratio of ε phase and the dislocation density, and grain refinement, which are caused by the high-strain induced by HPT processing.
AB - The effect of high-pressure torsion (HPT) processing on the microstructure and Vickers hardness of Co-Cr-Mo (CCM) alloys were investigated in this study. The microstructure of initial CCM alloy contains equiaxed grains with a grain diameter of approximately 50 μm and twins. The clear grain boundaries of equiaxed grains and twins disappear after HPT processing at a rotation number, N, of 10. The phase maps of initial CCM alloy and CCM alloy subjected to HPT processing at N = 5 measured by electron backscatter diffraction exhibit that the ratio of γ phase decreases from 93.5% to 34.1% and the ratio of ε phase increases from 6.5% to 65.9% by applying HPT processing. These results indicate that the ε phase is formed by high-strain, which is induced by the HPT processing. The Vickers hardness values on the surfaces of the CCM alloys subjected to HPT processing at N = 1, 5, and 10 increase with increasing the equivalent strain, εeq. These results suggest that an increase of Vickers hardness is correlated to an increase of the ratio of ε phase and the dislocation density, and grain refinement, which are caused by the high-strain induced by HPT processing.
KW - Co-Cr-Mo alloys
KW - Grain refinement
KW - High-pressure torsion
KW - Metallic biomaterial
KW - Strain-induced ε martensite phase
KW - Vickers hardness
UR - http://www.scopus.com/inward/record.url?scp=84903954304&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84903954304&partnerID=8YFLogxK
U2 - 10.4028/www.scientific.net/KEM.616.263
DO - 10.4028/www.scientific.net/KEM.616.263
M3 - Conference contribution
AN - SCOPUS:84903954304
SN - 9783038351306
T3 - Key Engineering Materials
SP - 263
EP - 269
BT - Advanced Ceramics and Novel Processing
PB - Trans Tech Publications Ltd
T2 - 5th International Symposium on Advanced Ceramics, ISAC 2013 and 3rd International Symposium on Advanced Synthesis and Processing Technology for Materials, ASPT 2013
Y2 - 9 December 2013 through 12 December 2013
ER -