Competitive understanding of hydrogen embrittlement and ductile fracture based on IMC particles in Al-Zn-Mg alloys

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K14037
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 18010:Mechanics of materials and materials-related
• Research Institution: Iwate University
• Principal Investigator: Shimizu Kazuyuki 岩手大学, 理工学部, 助教 (30748760)
• Project Period (FY): 2021-04-01 – 2023-03-31
• Keywords: 水素脆性 / アルミニウム合金 / 放射光X線CT / 変形破壊挙動 / 水素トラップ / 金属間化合物粒子 / Al-Zn-Mg合金

Outline of Final Research Achievements

Overcoming hydrogen embrittlement is a challenge in strengthening Al-Zn-Mg alloys. As a specific method to overcome this problem, dispersion of intermetallic compound particles has been proposed in this study. Using synchrotron 3D/4D fracture analysis and hydrogen partitioning analysis, the challenge of increasing the strength and ductility of Al-Zn-Mg alloys by particle dispersion was taken up.
Al7Cu2Fe and Mn-bearing particles were selected as the main intermetallic compound particles. The study has demonstrated both experimentally and computationally that Mn-bearing dispersoids with high internal hydrogen trapping capacity are formed in Mn-added alloys, and that hydrogen embrittlement is suppressed. The Mn particles are more finely morphologically controllable than Al7Cu2Fe, and are therefore strongly expected to contribute to improving the mechanical properties of the alloys.

Free Research Field

水素脆性

Academic Significance and Societal Importance of the Research Achievements

Al-Zn-Mg合金は代表的な高強度アルミニウム実用合金であり、航空機や新幹線など重量比強度が要求される部材に用いられている。輸送コストや環境負荷の観点から高強度化が希求されているが、水素脆化がそれを阻んでいた。本研究では、新しい水素脆化の克服法として粒子分散を学術的に探究した。合金の内部に墓相と異なる第二相を形成させ、これに水素を固定させるという視点は新奇であり、今後は学術的・産業的展開を大いに期待できる。