Direct observation and analysis of crack front morphology during crack pinning by heterogeneous interface

Abstract

Abstract. Adhesion of thin film multilayers deposited on glass is a crucial issue for many industrial applications. Thus, it becomes of great interest to measure and also to increase the adhesion. Many mechanisms of toughening a brittle solid can be found in literature; but few of them can be applied to thin film layer. By introducing a heterogeneous interfacial toughness field, it should be possible to increase adhesion. This toughness modification would be the consequence of the existence of a pinning regime due to a local change of the toughness. To experimentally validate this new approach of adhesion modification, we investigate the crack front pinning by performing cleavage tests on multilayer coated samples with a heterogeneous interfacial toughness. We have tested different patterns of pinning region. The crack front morphology was nicely described in the framework of the perturbative approach initially developed by Gao and Rice and allowed us to determine the local value of the energy release rate (~adhesion).

P‐10.4: A Protection Structure of the Foldable Display for Preventing the Macro‐Cracks

“…Besides the slits, the core idea of the special design was to import the interfaces of the metal and nitride/oxide, which could prevent the macro-cracks. The interfaces pinned the micro-cracks generated by bending and prevented them from propagating [2]. Therefore, the pinned micro-cracks were difficult to become macro-cracks which could penetrate the edge of TFE.…”