Mechanical properties of single-quasicrystalline AlCuCoSi

Wittmann, R.; Urban, K.; Schandl, Martin; Hornbogen, Erhard

doi:10.1557/jmr.1991.1165

Cited by 67 publications

(23 citation statements)

References 17 publications

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“…Tribological properties are of particular interest in quasicrystals, materials with atoms arranged in patterns with rotational symmetry but no translational periodicity, 15 because low coefficients of friction and low adhesion to polar liquids have been reported for surfaces in air [16][17][18][19] and also in vacuum studies. [20][21][22][23] The relationship between these anomalous surface properties and the surface atomic structure, however, is unclear.…”

Section: Introductionmentioning

confidence: 99%

Elastic and inelastic deformations of ethylene-passivated tenfold decagonalAl−Ni−Coquasicrystal surfaces

et al. 2005

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The adhesion and friction force properties between a tenfold Al-Ni-Co decagonal quasicrystal and a titanium nitride (TiN)-coated tip were investigated using an atomic force microscope in ultrahigh vacuum. To suppress the strong chemical adhesion found in the clean quasicrystal surfaces, the sample was exposed to ethylene that formed a protective passivating layer. We show that the deformation mechanism of the tip-substrate junction changes from elastic to inelastic at a threshold pressure of 3.8 to 4.0 GPa. Images of the indentation marks left above the threshold pressure indicate the absence of new steps, and indicate that surface damage is not accompanied by formation of slippage planes or dislocations, as found in plastically deforming crystalline materials. This is consistent with the lack of translational periodicity of quasicrystals. The work of adhesion in the inelastic regime is five times larger than in the elastic one, plausibly as a result of the displacement of the passivating layer. In the elastic regime, the friction dependence on load is accurately described by the Derjaguin-Müller-Toporov (DMT) model, consistent with the high hardness of both the TiN tip and the quasicrystal sample. Above the threshold pressure, the friction versus load curve deviates from the DMT model, indicating that chemical bond formation and rupture contribute to the energy dissipation. The adhesion and friction force properties between a tenfold Al-Ni-Co decagonal quasicrystal and a titanium nitride ͑TiN͒-coated tip were investigated using an atomic force microscope in ultrahigh vacuum. To suppress the strong chemical adhesion found in the clean quasicrystal surfaces, the sample was exposed to ethylene that formed a protective passivating layer. We show that the deformation mechanism of the tip-substrate junction changes from elastic to inelastic at a threshold pressure of 3.8 to 4.0 GPa. Images of the indentation marks left above the threshold pressure indicate the absence of new steps, and indicate that surface damage is not accompanied by formation of slippage planes or dislocations, as found in plastically deforming crystalline materials. This is consistent with the lack of translational periodicity of quasicrystals. The work of adhesion in the inelastic regime is five times larger than in the elastic one, plausibly as a result of the displacement of the passivating layer. In the elastic regime, the friction dependence on load is accurately described by the Derjaguin-Müller-Toporov ͑DMT͒ model, consistent with the high hardness of both the TiN tip and the quasicrystal sample. Above the threshold pressure, the friction versus load curve deviates from the DMT model, indicating that chemical bond formation and rupture contribute to the energy dissipation.

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Section: Introductionmentioning

confidence: 99%

Elastic and inelastic deformations of ethylene-passivated tenfold decagonalAl−Ni−Coquasicrystal surfaces

et al. 2005

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“…According to Wittman et al, 19 the Vickers hardness H 2N of the decagonal Al 62 Co 15 Cu 20 Si 13 quasicrystal shows a slight anisotropy, amounting to at most 5%, depending on whether the measurement was made on a surface perpendicular to the tenfold axis or parallel to it. Reducing the load on the Vickers indenter to 0.5N (the load used in Ref.…”

Section: Discussionmentioning

confidence: 97%

Friction anisotropy: A unique and intrinsic property of decagonal quasicrystals

et al. 2008

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We show that friction anisotropy is an intrinsic property of the atomic structure of Al-Ni-Co decagonal quasicrystals and not only of clean and well-ordered surfaces that can be prepared in vacuum [ J.Y. Park et al., Science 309, 1354 (2005)]. Friction anisotropy is manifested in both nanometer-size contacts obtained with sharp atomic force microscope tips and macroscopic contacts produced in pin-on-disk tribometers. We show that the friction anisotropy, which is not observed when an amorphous oxide film covers the surface, is recovered when the film is removed due to wear. Equally important is the loss of the friction anisotropy when the quasicrystalline order is destroyed due to cumulative wear. These results reveal the intimate connection between the mechanical properties of these materials and their peculiar atomic structure. KeywordsAmes Laboratory, Quasicrystal, Tribology, Scanning-probe microscopy (SPM) We show that friction anisotropy is an intrinsic property of the atomic structure of Al-Ni-Co decagonal quasicrystals and not only of clean and well-ordered surfaces that can be prepared in vacuum [J.Y. Park et al., Science 309, 1354(2005]. Friction anisotropy is manifested in both nanometer-size contacts obtained with sharp atomic force microscope tips and macroscopic contacts produced in pin-on-disk tribometers. We show that the friction anisotropy, which is not observed when an amorphous oxide film covers the surface, is recovered when the film is removed due to wear. Equally important is the loss of the friction anisotropy when the quasicrystalline order is destroyed due to cumulative wear. These results reveal the intimate connection between the mechanical properties of these materials and their peculiar atomic structure. Disciplines Materials Science and Engineering | Physical Chemistry

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“…One such property that might lead to important commercial and technological applications of these materials is their tribological behavior. Interestingly, there have been a number of reports of apparently low friction measured on the quasicrystal surfaces [90][91][92][93][94][95][96]. From a tribological science perspective, however, the interesting question is whether such behavior is a direct consequence of quasicrystallinity.…”

Section: Tribology Of Quasicrystalsmentioning

confidence: 99%