Microstructure and fracture of anomalous eutectic silicon-disilicide composites

Fischer, D.; Schuh, Christopher A.

doi:10.1016/j.intermet.2011.07.015

Cited by 14 publications

(17 citation statements)

References 56 publications

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“…Scanning electron micrographs of the Si‐(Cr,V)Si 2 composites [Figs. (c)–(f)] reveal anomalous eutectic microstructures similar to those observed and described in our previous study . In these micrographs, the dark and light‐colored phases correspond to the silicon and disilicide phase, respectively.…”

Section: Resultssupporting

confidence: 83%

“…In one of our previous studies, it was shown that the long‐crack fracture toughness of silicon (Si) could be improved by the incorporation of chromium‐vanadium disilicide [(Cr,V)Si 2 ] reinforcements via eutectic solidification to form silicon‐disilicide in situ composites, referred to as Si‐(Cr,V)Si 2 composites. Weak interfaces between the silicon and disilicide phases lead to crack deflection and bridging during crack propagation, and as a result, an increase in apparent toughness with increasing crack extension (i.e., a rising R‐curve) . To determine the potential of these composites as tribological components, it is of interest to explore whether the microstructural toughening mechanisms observed during the long‐crack response of Si‐(Cr,V)Si 2 composites impart a similar improvement in the short‐crack response of these materials during wear.…”

Section: Introductionmentioning

confidence: 99%

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Effect of a Rising R‐Curve on the Sliding Wear of Silicon‐Disilicide In Situ Composites

Fischer

Schuh

2012

J. Am. Ceram. Soc.

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This study investigates the tribological behavior of a new class of silicon-disilicide (Si-(Cr,V)Si 2 ) in situ composites which display eutectic microstructures comprising a Si matrix and reinforcing (Cr,V)Si 2 disilicide phase. Dry, room temperature ball-on-disk tests carried out at various loads (W = 1-6 N) showed that the specific wear rates of the Si-(Cr,V)Si 2 composites (k a %10 À5 mm 3 /Nm) were about an order of magnitude lower than that of unalloyed Si (k a %10 À4 mm 3 /Nm) in the wear regime dominated by lateral cracking. Microscopic analysis of the wear tracks, as well as observations from indentation experiments, revealed that the improved wear resistance of the Si-(Cr,V)Si 2 composites at higher loads was due to the activation of crack deflection and bridging toughening mechanisms during the wear process, which results in a rise in the apparent composite fracture toughness with increasing crack size (i.e., a rising R-curve behavior). Analysis of the wear test data in the context of a lateral fracture wear model demonstrates that the enhanced short-crack response of the Si-(Cr,V)Si 2 composites during sliding wear can indeed be explained by the incorporation of a sharply rising R-curve relation for the composite fracture toughness.W. M. Rainforth-contributing editor Manuscript No. 30343.

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Section: Resultssupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Effect of a Rising R‐Curve on the Sliding Wear of Silicon‐Disilicide In Situ Composites

Fischer

Schuh

2012

J. Am. Ceram. Soc.

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“…The method is also often practised on millimetrescale specimens (e.g. [45][46][47]), and it is consigned in ASTM standards [48,49].…”

Section: Introductionmentioning

confidence: 99%

Fracture toughness testing of nanocrystalline alumina and fused quartz using chevron-notched microbeams

et al. 2015

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We show that chevron-notched samples offer an attractive approach to the measurement of fracture toughness in micron-scale samples of brittle materials and use the method to characterize quartz and nanocrystalline alumina. Focused ion beam milling is used to carve bend bars of rectangular cross-section a few micrometres wide and containing a notch with a triangular ligament. Load-controlled testing is conducted using a nanoindentation apparatus. If the notch is appropriately machined, cracks nucleate and propagate in a stable fashion before becoming unstable. Sample dimensions are measured using a scanning electron microscope, and are used as input in finite element simulations of the bars' elastic deformation for various crack lengths. The calculated compliance calibration curve and the measured peak load then give the local fracture toughness of the material. Advantages of the method include a low sensitivity to environmental subcritical crack growth, and the fact that it measures toughness at the tip of a sharp crack situated in material unaffected by ion-milling. The approach is demonstrated on two materials, namely, monolithic fused quartz and nanocrystalline alumina Nextele 610 fibres; results for the latter give the intrinsic grain boundary toughness of alumina, free of grain bridging effects.

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“…As the impact and magnitude of these effects strongly depends on the architectural design of the material, the application of suitable optimal design approaches (see Section 4) is essential. Further improvements in the resolving power are constantly emerging [98]. Two-photon lithography is a very young technique and is evolving fast.…”

Section: Unique Benefits Of Two-photon Polymerizationmentioning

confidence: 99%

“…However, the line cross-section in the horizontal writing direction is always elliptical in shape, since, depending on the resin, the aspect ratio (height/width) of the voxel is in the range of 2.5-5.5 [98]. However, the line cross-section in the horizontal writing direction is always elliptical in shape, since, depending on the resin, the aspect ratio (height/width) of the voxel is in the range of 2.5-5.5 [98].…”

Section: Challenges In Fabrication Of 3d Architected Materials With 2mentioning

confidence: 99%

Fabrication of 3D Micro-Architected/Nano-Architected Materials

Valdevit

Bauer

2016

Three-Dimensional Microfabrication Using Two-Photon Polymerization

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Microstructure and fracture of anomalous eutectic silicon-disilicide composites

Cited by 14 publications

References 56 publications

Effect of a Rising R‐Curve on the Sliding Wear of Silicon‐Disilicide In Situ Composites

Effect of a Rising R‐Curve on the Sliding Wear of Silicon‐Disilicide In Situ Composites

Fracture toughness testing of nanocrystalline alumina and fused quartz using chevron-notched microbeams

Fabrication of 3D Micro-Architected/Nano-Architected Materials

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