Sunday, June 28, 2020
The analysis of deformation and failure mechanisms in small-scale devices and thin films is a critical issue, not yet solved. In this presentation, we describe recent advances and developments for the measurement of fracture toughness at small scales by the use of nanoindentation-based methods, including beam-bending methods and micro-pillar splitting. A critical comparison of the techniques is made, by testing a selected group of bulk and thin film materials. Additionally, the extension of the pillar splitting method to the use with different sharp indenters (from Berkovich to cube-corner) and its use for high-temperature and controlled environments testing are discussed. Finally, a couple of relevant case studies are presented, including Li-ion battery composites and thermal barrier coatings, in order to demonstrate that fast and reliable industrial application for such methods is possible.
References
[1] Sebastiani M, Johanns KE, Herbert EG et al. A novel pillar indentation splitting test for measuring fracture toughness of thin ceramic coatings. Philos. Mag. 2014; 95: 1928-1944.
[2] Sebastiani M, Johanns KE, Herbert EG et al. Measurement of fracture toughness by nanoindentation methods: Recent advances and future challenges. Curr. Opin. Solid St. M. 2015; 19: 324-333.
[3] Ghidelli, M., Sebastiani, M., Johanns, K and Pharr, G.M., Effects of indenter angle on micro-scale fracture toughness measurement by pillar splitting, Journal of the American Ceramic Society, 100(12), pp. 5731-5738.
