Corrosion behavior of Ti-6Al-4V alloy fabricated by selective laser melting in simulated spent fuel reprocessing environment
(1. CAS Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China;
2. School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China;
3. Shi-changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China)
2. School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China;
3. Shi-changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China)
Abstract: The corrosion behavior of Ti-6Al-4V fabricated by selective laser melting (SLM) in simulated spent fuel reprocessing environment was investigated. The microstructure and corrosion resistance of SLM Ti-6Al-4V alloy were characterized by optical microscopy, X-ray diffraction, scanning electron microscopy, electron backscatter diffraction and electrochemical tests. It can be found that SLM Ti-6Al-4V alloy has a better corrosion resistance than the cast counterpart in 6 mol/L hot nitric acid with oxidizing ions. Further analysis indicates that SLM Ti-6Al-4V alloy exhibits α？+β microstructure with smaller grain size and higher grain boundary density in comparison to the cast counterpart, and a higher β-Ti phase content with uniform distribution is also observed in SLM alloy, which is conducive to enhancing its passivation ability in nitric acid with oxidizing ions, contributing to an improved corrosion resistance. It is indicated that SLM Ti-6Al-4V alloy has the potential to be used in spent fuel reprocessing process.
Key words: spent fuel reprocessing; selective laser melting; Ti-6Al-4V alloy; corrosion behavior; passivation ability