Journal ArticleDOI
Effect of grain size on friction and wear of nanocrystalline aluminum
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In this article, the authors investigated the friction and wear characteristics of nanocrystalline aluminum as a function of grain size, and proposed an empirical equation based on the Archard's Law to describe the effect of grain refinement on the wear resistance under unlubricated sliding conditions.Abstract:
The friction and wear characteristics of nanocrystalline aluminum were investigated as a function of grain size. Nanocrystalline aluminum samples with an average diameter of 16.4 nm were produced using an r.f. magnetron sputtering technique. The grain size was increased (up to 98.0 nm) by an isothermal annealing treatment at 573 K. Hardness measurements were performed using an ultra-microhardness indentation system and it was observed that within the grain size range of 15–100 nm the hardness-grain size data could be well represented by the Hall-Petch relationship. Friction and wear measurements were made using a miniature pin-on-disk type tribometer under unlubricated conditions both in air and in vacuum. The coefficient of friction of aluminum tested against a stainless steel pin varied with the sliding distance. At the early stages of sliding the coefficient of friction rose to a peak value, and this was followed by a decrease to a steady-state value. The transition on the friction curve corresponded to a similar transition from a severe wear regime to a mild wear above a characteristic sliding distance on the cumulative volume loss versus sliding distance curve. The value of the peak coefficient of friction decreased from μp = 1.4 for aluminum with a coarse grain size (106 nm) to μp = 0.6 for the nanocrystalline aluminum with a grain size of 16.4 nm. The coefficient of friction of nanocrystalline aluminum showed a 30% increase when tested in vacuum. In the nanocrystalline grain range, the wear rates were found to be linearly dependent on the square root of the grain size. An empirical equation based on the Archard's Law is proposed to describe the effect of grain refinement on the wear resistance under unlubricated sliding conditions. A qualitative understanding of wear processes is developed in terms of the variation of the surface morphology and subsurface strength with sliding distance.read more
Citations
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Journal ArticleDOI
Some critical experiments on the strain-rate sensitivity of nanocrystalline nickel
TL;DR: In this paper, a simple computational model, predicated on the assumption that a rate-sensitive grain boundary affected zone exists, is shown to explain the observed effect of grain size on the rate-dependent plastic response.
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Sliding wear of nanocrystalline Ni-W: Structural evolution and the apparent breakdown of Archard scaling
TL;DR: In this article, a pin-on-disk wear testing of nanocrystalline Ni-W alloys with grain sizes of 3-47nm has been carried out and the extreme conditions produced during sliding wear are found to result in structural evolution and a deviation from Archard scaling for the finest grain sizes; in the finest nanocrystine materials wear resistance is higher than would be expected based on hardness alone.
Journal ArticleDOI
Effect of surface nanocrystallization on friction and wear properties in low carbon steel
TL;DR: In this paper, a nanocrystalline (nc) surface layer of about 10 μm thick was fabricated on a low carbon steel plate by means of surface mechanical attrition treatment, and the grain size is about 15 nm in the top surface layer, and it increases with an increase of depth from the treated surface.
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Metallic NEMS components fabricated from nanocomposite Al–Mo films
Zonghoon Lee,Colin Ophus,L. M. Fischer,N Nelson-Fitzpatrick,K. Westra,Stephane Evoy,Velimir Radmilovic,U. Dahmen,David Mitlin +8 more
TL;DR: In this article, a nano-electro-mechanical system (NEMS) cantilever was fabricated from metallic alloy nanocomposite films of Al-Mo. At thickness of 4.3 and 20.0 nm, these are the thinnest released metal cantilevers reported in the literature.
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Enhanced solid solution effects on the strength of nanocrystalline alloys
TL;DR: In this paper, solid solution strengthening in nanocrystalline alloys is studied using sputtered Ni-W as a model system, and the authors show that solute addition increases strength to very high levels, almost in proportion to the solute content.
References
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Book
The friction and lubrication of solids
Frank Philip Bowden,David Tabor +1 more
TL;DR: Tabor and Bowden as mentioned in this paper reviewed the many advances made in this field during the past 36 years and outlined the achievements of Frank Philip Bowden, and reviewed the behavior of non-metals, especially elastomers; elastohydrodynamic lubrication; and the wear of sliding surfaces.
Journal ArticleDOI
Contact and Rubbing of Flat Surfaces
TL;DR: In this article, the authors compared the deduced dependence of the experimental observables on the load with the experimental evidence and concluded that the most realistic model is one in which increasing the load increases both the number and size of the contact areas.
Book
Dislocations in solids
TL;DR: In this article, Bertotti, Ferro, and Mazetti proposed a theory of dislocation drag in covalent crystals and formed a model of the formation and evolution of dislocations during irradiation.
Journal ArticleDOI
A method for interpreting the data from depth-sensing indentation instruments
M. F. Doerner,William D. Nix +1 more
TL;DR: In this paper, a method for obtaining hardness and Young's modulus from the data obtained from these types of instruments is described, where the elastic displacements are determined from data obtained during unloading of the indentation.