Highly porous Ti-Co alloy specimens for biomedical applications were synthesized by powder metallurgy based space holder technique. Ti alloys have high melting temperature and affinity for oxygen, which makes Ti alloy...Highly porous Ti-Co alloy specimens for biomedical applications were synthesized by powder metallurgy based space holder technique. Ti alloys have high melting temperature and affinity for oxygen, which makes Ti alloys difficult to be processed. The Co addition reduces the melting temperature and Ti-Co alloy was sintered at lower temperatures. The electrochemical corrosion behaviour of the specimens was examined in the artificial saliva solution. The effects of Co content of the alloy, the p H value and fluoride concentration of the artificial saliva solution on the electrochemical corrosion properties of the specimens were investigated. The microstructure and mechanical properties of the specimens were examined. The electrochemical impedance spectroscopy results indicate that the corrosion resistance of the specimens decreases at high fluoride concentrations and low p H value. The defect density increases with increasing the fluoride concentration and decreasing the p H value of artificial saliva according to Mott-Schottky analysis.展开更多
The Co-Ni-Ti-V quaternary phase diagrams within the Co-Ni-rich region were investigated using the electron probe X-ray micro-analyzer(EPMA)and X-ray diffraction(XRD).Three isothermal sections corresponding to the Co-1...The Co-Ni-Ti-V quaternary phase diagrams within the Co-Ni-rich region were investigated using the electron probe X-ray micro-analyzer(EPMA)and X-ray diffraction(XRD).Three isothermal sections corresponding to the Co-10Ni-Ti-V,Co-15Ni-Ti-V,and Co-20Ni-Ti-V quaternary systems at 1000°C were experimentally established.The results indicate that increasing Ni content markedly broadens theγ(α-Co)andγ′(Co3Ti)two-phase regions.Based on the Co-Ni-Ti-V phase diagram,alloys with highγ′solvus temperature were designed,and their comprehensive properties,includingγ′coarsening behavior and mechanical properties,were thoroughly investigated.Compared to Co-Ti-based superalloys,the Co-20Ni-10Ti-10V alloy exhibits lower coarsening rates ofγ′precipitates andγ/γ′lattice mismatch.Notably,it possesses exceptional high-temperature mechanical properties,with a yield strength of 508 MPa at 1000°C.This superior performance is primarily attributed to the presence of a high density of stacking fault shear.展开更多
基金supported partially by Scientific Research Projects Coordination Unit of Istanbul University, Project numbers 42796 and 42922
文摘Highly porous Ti-Co alloy specimens for biomedical applications were synthesized by powder metallurgy based space holder technique. Ti alloys have high melting temperature and affinity for oxygen, which makes Ti alloys difficult to be processed. The Co addition reduces the melting temperature and Ti-Co alloy was sintered at lower temperatures. The electrochemical corrosion behaviour of the specimens was examined in the artificial saliva solution. The effects of Co content of the alloy, the p H value and fluoride concentration of the artificial saliva solution on the electrochemical corrosion properties of the specimens were investigated. The microstructure and mechanical properties of the specimens were examined. The electrochemical impedance spectroscopy results indicate that the corrosion resistance of the specimens decreases at high fluoride concentrations and low p H value. The defect density increases with increasing the fluoride concentration and decreasing the p H value of artificial saliva according to Mott-Schottky analysis.
基金supported by the National Natural Science Foundation of China(Nos.51831007,52371007)the Shenzhen Science and Technology Program,China(No.SGDX20210823104002016)the Guangdong Basic and Applied Basic Research Foundation,China(No.2021B1515120071).
文摘The Co-Ni-Ti-V quaternary phase diagrams within the Co-Ni-rich region were investigated using the electron probe X-ray micro-analyzer(EPMA)and X-ray diffraction(XRD).Three isothermal sections corresponding to the Co-10Ni-Ti-V,Co-15Ni-Ti-V,and Co-20Ni-Ti-V quaternary systems at 1000°C were experimentally established.The results indicate that increasing Ni content markedly broadens theγ(α-Co)andγ′(Co3Ti)two-phase regions.Based on the Co-Ni-Ti-V phase diagram,alloys with highγ′solvus temperature were designed,and their comprehensive properties,includingγ′coarsening behavior and mechanical properties,were thoroughly investigated.Compared to Co-Ti-based superalloys,the Co-20Ni-10Ti-10V alloy exhibits lower coarsening rates ofγ′precipitates andγ/γ′lattice mismatch.Notably,it possesses exceptional high-temperature mechanical properties,with a yield strength of 508 MPa at 1000°C.This superior performance is primarily attributed to the presence of a high density of stacking fault shear.
