Measuring fracture toughness of coatings using focused-ion-beam-machined microbeams

Abstract

Measuring the toughness of brittle coatings has always been a difficult task. Coatings are often too thin to easily prepare a freestanding sample of a defined geometry to use standard toughness measuring techniques. Using standard indentation techniques gives results influenced by the effect of the substrate. A new technique for measuring the toughness of coatings is described here. A precracked micro-beam was produced using focused ion beam (FIB) machining, then imaged and loaded to fracture using a nanoindenter.

Recent progress in research on tungsten materials for nuclear fusion applications in Europe

“…Focused ion beam machining has been used to manufacture small cantilevers (H25µm x 4µm x 6µm) ( Fig. 10), which are then deflected to fracture using a nano-indenter, to measure the fracture 13 toughness of single grain boundaries [25][26][27]. Initial results (Fig.…”

Inducing stable interfacial delamination in a multilayer system by four-point bending of microbridges

“…The detailed milling procedure can be found elsewhere [33,34]. The MBs were examined using a 7100F scanning electron microscope (SEM) (JEOL Ltd., Tokyo, Japan Fig.…”

An Investigation into Fracture of Multi-Crystalline Silicon

“…A notch was inserted normal to the long axis. The nanoindenter was used to measure the fracture load and this was converted, using the analysis described in [4] using dimensions measured from secondary electron images, to give a mean fracture toughness of 0.7MPam 1/2 , with a standard deviation of 0.3MPam 1/2 . Within experimental error, this is consistent with the known value of fracture toughness for this fracture plane of 0.89MPam 1/2 [9].…”

“…In recent years, with the increased availability of focused ion beam (FIB) machining and related techniques, micromechanical methods have developed which enable the properties of very small regions of crystals to be tested [2][3][4][5][6]. The advantage of these techniques is that they allow the mechanical effects of specific defects to be determined.…”

“…In this paper, a micromechanical technique is applied to mc-Si to investigate the mechanical properties of individual grain boundaries. Existing methods [4] which use a FIB to prepare micron-scale cantilever specimens are applied to mc-Si. Compared to many materials, directionally-solidified mc-Si is a straightforward system on which to perform such experiments, as the grain boundaries run approximately normal to the wafer surface.…”