Effects of alloy compositions on hydrogen behaviors at a nickel grain boundary and a coherent twin boundary |
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| Affiliation: | 1. Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-Sen University, Zhuhai, 519082, China;2. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China;1. School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China;2. Shanghai Key Laboratory of High Temperature Materials and Precision Forming, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240, China;3. Themo Fisher Scientific, 399 Sheng Xia Road, Shanghai 201210, China;1. CAS Key Laboratory of Nuclear Materials and Safety Assessment, IMR (NMSA), Shenyang 110014, PR China;2. Shenyang National Laboratory of Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, PR China;3. Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, PR China;1. School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia;2. School of Chemistry, University of Sydney, Sydney, NSW, 2006, Australia;1. School of Materials Science and Engineering, Beihang University, Beijing 100191, China;2. Center for Integrated Computational Materials Engineering, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, China |
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| Abstract: | The effects of several common metallic and nonmetal alloy compositions (i.e., Cr, Mo, B, and P) on the energetics and kinetics of hydrogen behaviors at a nickel grain boundary (GB) and a coherent twin boundary (CTB) were systematically investigated by first-principles calculations. H, Cr, Mo, B, and P have a stronger segregation into Ni GB than Ni CTB due to the presence of a cavity in GB. Cr, Mo, B, and P all act as obstacles for H segregation and diffusion in both GB and CTB, but the physical mechanisms are different: In Ni GB, Cr and Mo result in the shrinkage of isosurfaces of optimal charge densities for H, and B and P provide a strong competitive tendency to accumulate into the GB; in Ni CTB, Cr and Mo induce charge accumulation, and B and P result in a repulsive interaction to H. The present study provides the microscopic images of H compositions in Ni GB and CTB under the effects of alloy compositions; this is essential for understanding the mechanism of hydrogen embrittlement (HE) and improving the ability of alloys against HE. |
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| Keywords: | First-principles calculation Hydrogen Nickel Alloy composition Grain boundary Coherent twin boundary |
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