Investigation of multiplication process of crack tip dislocations by 4D-HVEM-tomograph

Research Project

Project/Area Number	15K21250
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Multi-year Fund
Research Field	Structural/Functional materials Materials/Mechanics of materials
Research Institution	Kagoshima University
Principal Investigator	SADAMATSU Sunao 鹿児島大学, 理工学域工学系, 助教 (10709554)
Research Collaborator	YAMAZAKI Syunji
Project Period (FY)	2015-04-01 – 2018-03-31
Project Status	Completed (Fiscal Year 2017)
Budget Amount *help	¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000) Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000) Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000) Fiscal Year 2015: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Keywords	脆性破壊 / 脆性－延性遷移 / 転位 / 亀裂 / 電子顕微鏡 / 構造材料 / 金属物性 / 靭性 / 金属強度 / 超高圧電子顕微鏡 / 電子線トモグラフィー / 力学的性質 / 脆性-延性遷移
Outline of Final Research Achievements	We investigated the stress shielding effect of dislocations away from the crack tip by observing dislocation generated in the tip of crack in silicon in a wide area.The result shows that the dislocations were found to have a different character from the dislocations near the crack tip. The local stress intensity factor by these dislocations was calculated and found to be a dislocation that cancels the stress intensity factor of mode II and mode III of dislocation existing at the crack tip.Therefore, It is found that the stress is applied, the dislocation occurring and increasing there shields this mode, and the other modes are generated and multiplied so as to cancel each other.