Microstructural dependence of the fracture toughness of metallic thin films: A bulge test and atomistic simulation study on single-crystalline and polycrystalline silver films

Preiß E, Lyu H, Liebig JP, Richter G, Gannott F, Gruber PA, Göken M, Bitzek E, Merle B (2019)


Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2019

Journal

Book Volume: 34

Pages Range: 3483-3494

Journal Issue: 20

URI: https://www.cambridge.org/core/journals/journal-of-materials-research/article/microstructural-dependence-of-the-fracture-toughness-of-metallic-thin-films-a-bulge-test-and-atomistic-simulation-study-on-singlecrystalline-and-polycrystalline-silver-films/73FEF9FD56EFF314E1366003EFFE8C5B#

DOI: 10.1557/jmr.2019.262

Open Access Link: https://www.cambridge.org/core/journals/journal-of-materials-research/article/microstructural-dependence-of-the-fracture-toughness-of-metallic-thin-films-a-bulge-test-and-atomistic-simulation-study-on-singlecrystalline-and-polycrystalline-silver-film

Abstract

The microstructure contribution to the very low fracture toughness of freestanding metallic thin films was investigated by bulge fracture tests on 200-nm-thick {100} single-crystalline and polycrystalline silver films. The single-crystalline films exhibited a significantly lower fracture toughness value (KIC = 0.88 MPa m1/2) than their polycrystalline counterparts (KIC = 1.45 MPa m1/2), which was rationalized by the observation of an unusual crack initiation behavior - characterized by twinning in front of the notch tip - during in situ testing in the atomic force microscope. Twinning was also observed as a dominant deformation mechanism in atomistic simulations. This twinning tendency is explained by comparing the resolved shear stresses acting on the leading partial dislocation and the full dislocation, which allows to develop a size- and orientation-dependent twinning criterion. The fracture toughness of polycrystalline samples was found to be higher because of the energy dissipation associated with full dislocation plasticity and because of crack meandering along grain boundaries.

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APA:

Preiß, E., Lyu, H., Liebig, J.P., Richter, G., Gannott, F., Gruber, P.A.,... Merle, B. (2019). Microstructural dependence of the fracture toughness of metallic thin films: A bulge test and atomistic simulation study on single-crystalline and polycrystalline silver films. Journal of Materials Research, 34(20), 3483-3494. https://dx.doi.org/10.1557/jmr.2019.262

MLA:

Preiß, Eva, et al. "Microstructural dependence of the fracture toughness of metallic thin films: A bulge test and atomistic simulation study on single-crystalline and polycrystalline silver films." Journal of Materials Research 34.20 (2019): 3483-3494.

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