Analysis of necking behavior in ultrafine-grained material by optical strain measurement

Research Project

Project/Area Number	21760586
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Single-year Grants
Research Field	Material processing/treatments
Research Institution	Kyoto University
Principal Investigator	TERADA Daisuke Kyoto University, 大学院・工学研究科, 助教 (80432524)
Project Period (FY)	2009 – 2010
Project Status	Completed (Fiscal Year 2010)
Budget Amount *help	¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000) Fiscal Year 2010: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000) Fiscal Year 2009: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
Keywords	超微細粒材料 / 延性 / 力学特性 / くびれ進展挙動 / 光学的全視野ひずみ計測法 / 光学的全視野ひずみ測定法 / 画像相関法 / アルミニウム / 超微細粒組織 / くびれ変形 / 光学的全視野ひずみ測定
Research Abstract	Necking behavior in tensile test of ultrafine grained aluminum was analyzed by full-field optical strain measurement method. Fracture strain was larger than 30% in the aluminum whose mean grain size was larger than 1.7μm. In the specimens, most of the gage region of tensile specimen was deformed when necking started. The necking region became narrower with increasing the tensile strain. The specimen having mean grain size of 0.24μm showed fracture strain of 9%. The necking region of the specimen with grain size of 0.24μm was narrower than that of the specimens whose mean grain size was larger than 1.7μm.