Atomic simulations of suppression of cracks in twins of Ti

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K23570
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0401:Materials engineering, chemical engineering, and related fields
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Miyazawa Naoki 東京工業大学, 物質理工学院, 助教 (40847787)
• Project Period (FY): 2019-08-30 – 2021-03-31
• Keywords: 分子動力学 / 第一原理計算 / チタン / 双晶 / 粒界

Outline of Final Research Achievements

The effect of oxygen on the strength of twins and grain boundaries in Ti was studied using molecular dynamics simulation. In addition, to investigate various kinds of additional elements, the effect of segregated atoms on the strength of twist grain boundaries in Mg was investigated. The results showed that segregated elements enhanced the strength of boundaries when they segregate at the boundary and in high concentration. On the other hand, dislocations can easily transmit across boundaries when additional atoms segregated non-boundary sites or low concentration. In this case, the boundary strength was not enhanced. The results of molecular dynamics simulation was compared with first-principles calculation. As a result, the strength of boundaries was increased when solutes and matrix atoms formed covalent-like bonds.

Free Research Field

計算材料科学

Academic Significance and Societal Importance of the Research Achievements

これまで分子動力学法を用いてチタンの界面強度に及ぼす固溶元素の影響を調べた研究は限られていた．従来の研究では第一原理計算を用いて固溶原子の静的な電子状態を調査した研究が主であり，転位と双晶の相互作用のような動的な解析についてはほとんど行われてこなかった．本研究では置換型元素である酸素の強化機構が置換型元素と大きく異なることを明らかにしたことに学術的な意義がある．また第一原理計算と比較することで電子状態と転位の運動論を結び付けたことは材料設計における電子論の有用性を示したと言え、社会的にも意義があると考えられる．