Length-scale-controlled fatigue mechanisms in thin copper films

Zhang, Guangping; Volkert, Cynthia A.; Schwaiger, Ruth; Wellner, P.; Arzt, Eduard; Kraft, O.

doi:10.1016/j.actamat.2006.03.013

Cited by 168 publications

(97 citation statements)

References 38 publications

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“…Hence, although the orientation relationship between the coarsened grain and the next neighbouring grain may be satisfied, the nanotwin-assisted mechanism may not have the grains to grow so large that fatigue extrusions/intrusions are able to form, as observed in ultrafine grains produced by severe plastic deformation 46 . In the ultrafine grains with highly stored deformation energy, the thermally activated dynamic recovery resulted in grain coarsening and subsequent cyclic softening 2 , while the limited grain coarsening in the present nano-grained films led to the fact that the initiation of fatigue cracks is still rather difficult in these coarsened grains less than 100 nm 34 . Furthermore, such nanotwin-assisted grain growth may effectively dissipate some amount of cyclic plasticity, and thus partially contribute to enhanced fatigue properties of the 20-nmthick gold films compared to that of 900-nm-thick ones, as shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

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Nanotwin-assisted grain growth in nanocrystalline gold films under cyclic loading

2014

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Under mechanical loading, nanocrystalline metals show unique behaviour, among the most common of which are high strength, mechanically induced grain growth and twin formation. However, mechanically induced grain growth is seldom correlated with twins. Here we report a clear relationship between grain growth and nanoscale twins in 20-nm-thick gold films with a grain size of B19 nm under cyclic loading based on atomic-scale observations and analyses. We find that the formation of nanotwins is an effective way to assist grain coarsening, following a fundamental process that the mutual formation of nanotwins in two neighbouring grains changes the local grain orientation and dissociates the grain boundary into new segments, which become more mobile. The proposed mechanism of nanotwin-assisted grain growth may have important implications for understanding the interface-mediated mechanisms of cyclic plastic deformation and for the interface engineering design of nanostructured metals with both high strength and good fatigue resistance.

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Section: Discussionmentioning

confidence: 99%

“…Features of fatigue damage in the gold film (Fig. 2a) mainly exhibit multiple cracks without any bulk-like fatigue extrusions/intrusions induced by cyclic strain localization 34 . Then, we carefully checked the cyclically deformed regions far away from and near the cracks, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Nanotwin-assisted grain growth in nanocrystalline gold films under cyclic loading

2014

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“…Fatigue damage in the LCF and HCF regimes is sensitive to microstructural parameters like grain size and film thickness [8] with the trend that lifetime increases with decreasing film thickness and grain size. Zhang et al [5] reported that film thickness and grain size have similar effects on the fatigue damage and, since the film thickness limits the grain size in such films, it is difficult to differentiate between these effects. Extensive investigations using transmission electron microscopy (TEM) on Cu thin films revealed that the formation of dislocation structures changes considerably with film thickness and grain size [5].…”

Section: Fatigue In Thin Filmsmentioning

confidence: 99%

“…Zhang et al [5] reported that film thickness and grain size have similar effects on the fatigue damage and, since the film thickness limits the grain size in such films, it is difficult to differentiate between these effects. Extensive investigations using transmission electron microscopy (TEM) on Cu thin films revealed that the formation of dislocation structures changes considerably with film thickness and grain size [5]. Thin films of 3 µm thickness still show bulk-like fatigue damage, with clear dislocation structures.…”

Section: Fatigue In Thin Filmsmentioning

confidence: 99%

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A novel high-throughput fatigue testing method for metallic thin films

Burger

Eberl

Siegel

et al. 2011

Science and Technology of Advanced Materials

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Thin films are used in a wide variety of computing and communication applications although their fatigue behavior and its dependence on alloying elements are not very well known. In this paper, we present an experimental implementation of a novel high-throughput fatigue testing method for metallic thin films. The methodology uses the fact that the surface strain amplitude of a vibrating cantilever decreases linearly from the fixed end to the free end. Therefore, a thin film attached to a vibrating cantilever will experience a gradient of strain and corresponding stress amplitudes along the cantilever. Each cantilever can be used to extract a lifetime diagram by measuring the fatigue-induced damage front that progresses along the cantilever during up to 10 8 load cycles.

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Fatigue Damage Behavior of Freestanding 40 µm‐Thick Nickel Foils for MEMS Applications

Zhang

2013

Adv Eng Mater

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Fatigue damage behavior of freestanding 40 mm-thick Ni foils was investigated. We found that there were evident differences in fatigue behaviors of the foils loaded normal to and parallel to the rolling direction. EBSD analyses revealed that fatigue cracking along grain boundaries (GBs) or slip bands in two kinds of the foils depended on the difference in Schmid factor of the grains along both sides of the GBs and the misorientation angle of the GB. Fatigue damage mechanism was discussed. 496 wileyonlinelibrary.com ß Fatigue Damage Behavior of Freestanding . . .Fig. 4. SEM images of fatigue damage behavior of (a) and (b) RD-loaded and (c) and (d) TD-loaded specimens. The arrows indicate the LD and RD. ADVANCED ENGINEERING MATERIALS 2013, 15, No. 6

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Length-scale-controlled fatigue mechanisms in thin copper films

Cited by 168 publications

References 38 publications

Nanotwin-assisted grain growth in nanocrystalline gold films under cyclic loading

Nanotwin-assisted grain growth in nanocrystalline gold films under cyclic loading

A novel high-throughput fatigue testing method for metallic thin films

Fatigue Damage Behavior of Freestanding 40 µm‐Thick Nickel Foils for MEMS Applications

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