Evaluation of large-strain plasticity of nano-films by a hybrid digital image correlation method

2014 Fiscal Year Final Research Report

• Project/Area Number: 25630012
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Materials/Mechanics of materials
• Research Institution: Osaka University
• Principal Investigator: MINOSHIMA Kohji 大阪大学, 工学(系)研究科(研究院), 教授 (50174107)
• Co-Investigator(Kenkyū-buntansha): HIRAKATA Hiroyuki 大阪大学, 大学院工学研究科, 准教授 (40362454)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 薄膜 / 塑性変形特性

Outline of Final Research Achievements

We developed a method for estimating large-strain plasticity of metallic nano-films on the basis of local large-strain deformation field, which was intentionally introduced and was evaluated by a digital image correlation (DIC) method. We conducted in situ field emission scanning electron microscopy (FESEM) tensile testing for a 500-nm-thick Cu film with a notch, and evaluated the large-strain deformation field around the notch root by DIC. Based on the deformation field, we estimated the plastic properties of the films with the aid of elastic-plastic finite element analysis. This method enabled us to estimate large-strain plasticity up to ~6% of the films whose fracture strain was less than 1% in conventional tensile testing. As an application, we applied the method to the fatigue crack closure of Cu films. The results showed that the method could quantitatively evaluate the fatigue crack closure.

Free Research Field

材料強度学