QUANTIFICATION OF INTERFACE STRENGTH OF A THIN FILM USING A NEW MICROCANTILEVER GEOMETRY.
Eloho OkoteteGrand Ballroom B
Interfaces failure occurs not only in structural materials but also in functional material systems including systems for energy conversion and storage. Such failures lead to degradation of mechanical and functional properties, such as battery capacity or electrical conductivity. In bulk scale, there are various experimental methods to investigate the interface strength and its failure mechanisms, for instance, peeling test, superlayer test, or indentation test. One of the disadvantages of these approaches is that it can be applied only to relatively thick coatings [1,2]. Small-scale mechanical testing is a powerful tool for studying interface properties because it can quantify micro- and nanometer-sized thin films, and individual interfaces of interest can be tested by isolating them using focused ion beam (FIB). Single and double cantilever beams have been used to investigate fracture/delamination properties of single interfaces [3,4], however, these methods are prone to experimental imperfections arising from testing geometries.
In this talk, we propose a new in situ scanning electron microscope (SEM) microcantilever design that provides reliable and quantitative interface toughness. In addition, the optimized geometry can promote a pre-notch (or crack) to propagate in a stable manner, which is important to generate a natural crack front without FIB-induced damage/artifacts.