Annealed microstructure dependent corrosion behavior of Ti-6Al-3Nb-2Zr-1Mo alloy
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2021年第3期
论文作者：Baoxian Su Liangshun Luo Binbin Wang Yanqing Su Liang Wang Robert O.Ritchie Enyu Guo Ting Li Huimin Yang Haiguang Huang Jingjie Guo Hengzhi Fu
文章页码：234 - 248
摘 要：Corrosion resistance of titanium（Ti） alloys is closely connected with their microstructure which can be adjusted and controlled via different annealing schemes.Herein,we systematically investigate the specific effects of annealing on the corrosion performance of Ti-6 Al-3 Nb-2 Zr-1 Mo（Ti80） alloy in 3.5 wt.% NaCl and 5 M HCl solutions,respectively,based on open circuit potential（OCP）,potentiodynamic polarization,electrochemical impedance spectroscopy（EIS）,static immersion tests and surface analysis.Results indicate that increasing annealing tempe rature endows Ti80 alloy with a higher volume fraction of β phase and finer α phase,which in turn improves its corrosion resistance.Surface characterization demonstrates that β phase is more resistant to corrosion than α phase owing to a higher content of Nb,Mo,and Zr in the former;additionally,the decreased thickness of a phase alleviates segregation of elements to further restrain the micro-galvanic couple effects between α and β phases.Meanwhile,the influential mechanisms of environmental conditions on corrosion of Ti80 alloy are discussed in detail.As the formation of a highly compact and stable oxide film on surface,annealed Ti80 alloys exhibit a low corrosion current density(10-6 A/cm2) and high polarization impedance（106 Ω·cm2） in 3.5 wt.% NaCl solution.However,they suffer severe corrosion in 5 M HCl solution,resulting from the breakdown of native oxide films(the conversion of TiO2 to aqueous Ti3+),active dissolution of substrate Ti to aqueous Ti3+ and existence of micro-galvanic couple effects.Those findings could provide new insights to designing Ti alloys with high-corrosion resistance through microstructural optimization.
Baoxian Su1，Liangshun Luo1，Binbin Wang1，Yanqing Su1，Liang Wang1，Robert O.Ritchie2，Enyu Guo3，Ting Li4，Huimin Yang5，Haiguang Huang6,7，Jingjie Guo1，Hengzhi Fu1
1. National Key Laboratory for Precision Hot Processing of Metals, School of Materials Science and Engineering, Harbin Institute of Technology2. Department of Materials Science and Engineering, University of California3. Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province), School of Materials Science & Engineering, Dalian University of Technology4. Department of Materials Science and Engineering, Dalian Maritime University5. School of Materials and Chemical Engineering, Heilongjiang Institute of Technology6. School of Materials Science and Engineering, Kunming University of Science and Technology7. Yunnan Titanium Industry Co., Ltd.
摘 要：Corrosion resistance of titanium（Ti） alloys is closely connected with their microstructure which can be adjusted and controlled via different annealing schemes.Herein,we systematically investigate the specific effects of annealing on the corrosion performance of Ti-6 Al-3 Nb-2 Zr-1 Mo（Ti80） alloy in 3.5 wt.% NaCl and 5 M HCl solutions,respectively,based on open circuit potential（OCP）,potentiodynamic polarization,electrochemical impedance spectroscopy（EIS）,static immersion tests and surface analysis.Results indicate that increasing annealing tempe rature endows Ti80 alloy with a higher volume fraction of β phase and finer α phase,which in turn improves its corrosion resistance.Surface characterization demonstrates that β phase is more resistant to corrosion than α phase owing to a higher content of Nb,Mo,and Zr in the former;additionally,the decreased thickness of a phase alleviates segregation of elements to further restrain the micro-galvanic couple effects between α and β phases.Meanwhile,the influential mechanisms of environmental conditions on corrosion of Ti80 alloy are discussed in detail.As the formation of a highly compact and stable oxide film on surface,annealed Ti80 alloys exhibit a low corrosion current density(10-6 A/cm2) and high polarization impedance（106 Ω·cm2） in 3.5 wt.% NaCl solution.However,they suffer severe corrosion in 5 M HCl solution,resulting from the breakdown of native oxide films(the conversion of TiO2 to aqueous Ti3+),active dissolution of substrate Ti to aqueous Ti3+ and existence of micro-galvanic couple effects.Those findings could provide new insights to designing Ti alloys with high-corrosion resistance through microstructural optimization.
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