Papers by Keyword: Interfacial Toughness

Abstract: Cross-sectional nanoindentation (CSN) is a new method for measuring interface adhesion of thin films. The interfacial energy release rate (G), characterizing interfacial adhesion, is calculated from the material and geometrical parameters relevant to the test. Effects of residual stresses on G and crack tip phase angle Ψ, have been studied by finite element simulation in this study. The results show tensile residual stresses increase G and compressive stresses reduce it, and they have similar effects on the magnitude of Ψ.

Abstract: This study combined microscratch test and fracture-mechanical analysis to assess the interfacial reliability of Nafion and Pt/Ru catalyst layers in micro fuel cells. Scratch test was used to determine the critical load for interfacial failure, while fracture-mechanical analysis was used to quantify the adhesion between Nafion (the electrolyte polymer substrate) and Pt/Ru alloy (catalyst coating). We also proposed a key of solving ambiguous problems in indentation cracking test by determining geometric information from crack propagation and critical points, as for a hard porous coating on a soft substrate. A comparative analysis of three coating methods, spray, decalcomania and their mixed process, was done to assess the validity of our new method.

Abstract: A new specimen is proposed to measure the interfacial toughness between the Al-0.5%Cu thin film and the Si substrate. The plain and general micro-fabrication processes are sufficient to fabricate the specimen. With the help of the finite element method and the concepts of the linear elastic fracture mechanics, the detailed structure for this specimen is modeled and evaluated. The results obtained from this research show that the proposed specimen provides efficient and convenient method to measure the interfacial toughness between the Al-Cu thin film and the Si substrate.