Elucidation of abnormal phenomena of elongation increase induced by He in metal

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K06423
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Physical properties of metals/Metal-base materials
• Research Institution: Kyoto University
• Principal Investigator: Xu Qiu 京都大学, 原子炉実験所, 准教授 (90273531)
• Co-Investigator(Kenkyū-buntansha): 張 倹 京都大学, 原子炉実験所, 技術職員 (30379010)
• Research Collaborator: LUO Laima 合肥工業大学, 准教授 ; CAO Xingzhong 高エネルギー物理研究所, 准教授 ; WANG Yuxia 復旦大学, 准教授
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 鉄 / 力学特性 / 転位 / 原子空孔 / ヘリウム / 水素

Outline of Final Research Achievements

He atoms are insoluble in most metals, and the presence of He atoms in metals decreases the ductility. Recently, however, Xu et al. indicated that He implantation increased the total elongation of pure Fe and Ni containing only dislocations. In order to understand the mechanism of this phenomenon, the interaction between He atoms and defects in Fe was investigated. He atoms were trapped at the dislocations in Fe containing only dislocations when He was implanted. The He atoms were once released from the dislocation during tension and were trapped again at vacancies induced by tension. Therefore, vacancy aggregation, in other words, the nucleation and growth of cracks were suppressed. As a result, elongation increased. By this method, hydrogen embrittlement in iron is also reduced.

Free Research Field

原子力材料