Development of reemission positron microscope

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K14015
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Analytical chemistry
• Research Institution: Chiba University
• Principal Investigator: Fujinami Masanori 千葉大学, 大学院工学研究院, 教授 (50311436)
• Research Collaborator: CHIARI Luca 千葉大学, 大学院工学研究院, 特任助教 ; KOMATSU Akari 千葉大学, 大学院工学研究科, 大学院生 ; NOZAKI Ayaka 千葉大学, 大学院工学研究科, 大学院生 ; KOIZUMI Kazuki 千葉大学, 大学院工学研究科, 大学院生 ; SENDA Tomoki 千葉大学, 大学院工学研究科, 大学院生
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: 格子欠陥 / 放射線 / 量子ビーム / 陽電子 / 水素脆化 / 鉄 / ステンレス鋼

Outline of Final Research Achievements

The aim of this work is to clarify the crucial defects related to hydrgen embrittelment (HE) in pure bcc-iron and austenitic stainless steel by positron annihilation lifetime spectroscopy(PALS). Pure bcc-iron specimens were deformed at two different strain rates under a hydrogen environment. These PALS results could be explained by the formation of vacancy-hydrogen complexes, which were considered the dominant defects in HE. The two types of austenitic stainless steels, SUS 304 and SUS 316L, were pre-charged with hydrogen and subjected to tensile straining. The SUS 304 alloy showed HE, whereas the SUS 316L alloy showed low hydrogen susceptibility. The vacancy clusters could be induced in both of the samples, indicating that they were not crucial in the HE process. By comparing the defect behavior in detail using the PALS method, we can clarify the vacancy-hydrogen complexes which are related to HE in fcc iron.

Free Research Field

分析化学