Study on fracture toughness unifying nanomaterials science and micro fracture mechanics.

2017 Fiscal Year Final Research Report

• Project/Area Number: 26249106
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Structural/Functional materials
• Research Institution: Sasebo National College of Technology (2016-2017); Kyushu University (2014-2015)
• Principal Investigator: Higashida Kenji 佐世保工業高等専門学校, その他, 校長 (70156561)
• Co-Investigator(Kenkyū-buntansha): 田中 將己 九州大学, 工学研究院, 准教授 (40452809) ; 森川 龍哉 九州大学, 工学研究院, 助教 (00274506) ; 定松 直 鹿児島大学, 理工学域工学系, 助教 (10709554)
• Co-Investigator(Renkei-kenkyūsha): MATSUMURA Syo 九州大学, 工学研究院, 教授 (60150520) ; SHIMOKAWA Tomotsugu 金沢大学, 理工研究域, 教授 (40361977) ; YAMAGUCHI Masatake 原子力研究開発機構, システム計算科学センター, 研究員 (50360417)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: 破壊 / 転位

Outline of Final Research Achievements

Cracks were introduced on a specimen cut from a {011} silicon wafer by using a Vickers indenter. The sample was heated in order to introduce dislocations at the crack tip. The crack tip dislocations were observed by using high-voltage electron microscope, determining both three-dimensional structures and Burgers vectors of the dislocations at the crack tip. It was found that those dislocations shield the crack tip efficiently, which increases fracture toughness. In addition to that, the activation energy for controlling process of the brittle-to-ductile transition temperature was measured from the dependence of the transition temperature on the deformation rate. It was found the value is close to that of dislocation glide at 50K in the condition of the strain rate employed in the tensile tests performed in this study.

Free Research Field

金属強度学