Reduction in anisotropic response of corrosion properties of selective laser melted Co-Cr-Mo alloys by post-heat treatment
| Autor: | Atsushi Takaichi, Takao Hanawa, Yusuke Tsutsumi, Hein Linn Htat, Nuttaphon Kittikundecha, Yuka Kajima, Takayuki Yoneyama, Noriyuki Wakabayashi, Hla Htoot Wai Cho |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Hot Temperature Surface Properties 02 engineering and technology Corrosion 03 medical and health sciences 0302 clinical medicine Alloys General Materials Science Selective laser melting Composite material Anisotropy Polarization (electrochemistry) General Dentistry Lasers Isotropy Reproducibility of Results Vertical plane 030206 dentistry 021001 nanoscience & nanotechnology Horizontal plane Microstructure Mechanics of Materials Chromium Alloys 0210 nano-technology Dental Alloys |
| Zdroj: | Dental materials : official publication of the Academy of Dental Materials. 37(3) |
| ISSN: | 1879-0097 |
| Popis: | Objectives The application of selective laser melting (SLM) to dentistry has been rapidly expanding; however, SLM-processed parts possess orientation-dependent properties (i.e., anisotropy) that can affect the long-term reliability of the dental prostheses. This study aimed to evaluate the anisotropic corrosion response of SLM-processed Co–Cr–Mo alloys under various heat treatments. Methods Samples fabricated via SLM along the horizontal plane (x-y plane) and vertical plane (x-z plane), with respect to the build direction, were subjected to various heat treatments. The resulting microstructures of the samples were characterized, and their corrosion properties were evaluated using anodic polarization and immersion tests. Results All samples showed similar transpassive behavior of the polarization curves. However, the immersion tests showed that the as-built x-z plane samples released significantly more metal ions than those fabricated on the x-y plane because of the larger area of preferentially corroded molten pool boundaries (MPBs) in the x-z plane samples. Our results further demonstrated that the heat treatments eliminated the MPBs, resulting in isotropic corrosion properties. However, excessive heat treatment at high temperatures induces the formation of coarse precipitates, resulting in a less-protective passive film. Significance The post-build heat treatments at temperatures that eliminate the MPBs are effective in reducing anisotropic corrosion behavior, and the lowest possible temperature is suitable for reducing the amount of released metal ions. These findings are expected to facilitate the application of SLM in dentistry to allow fast and precise production of prosthetic devices. |
| Databáze: | OpenAIRE |
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