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Journal ArticleDOI

Synergetic Effect of Cryorolling and Postroll Aging on Simultaneous Increase in Wear Resistance and Mechanical Properties of an Al–Cu Alloy

01 Nov 2018-Journal of Tribology-transactions of The Asme (American Society of Mechanical Engineers)-Vol. 140, Iss: 6, pp 061607
TL;DR: In this paper, an attempt has been made to simultaneously enhance the wear resistance and mechanical properties of an Al-Cu alloy, AA2014 by imparting different levels of cryorolling strains and postroll aging treatment.
Abstract: Aluminum–copper alloy system is extensively used in structural and aerospace applications for its high strength-to-weight ratio, good mechanical and tribological properties. Improving the properties of these alloys would likely widen their application area. In the present work, an attempt has been made to simultaneously enhance the wear resistance and mechanical properties of an Al–Cu alloy, AA2014 by imparting different levels of cryorolling strains and postroll aging treatment. The wear behavior of the material is studied under dry sliding condition by pin-on-disk experiments and mechanical properties are assessed by tensile test. Formation of high fraction of dislocation density and significant refinement of microstructure during cryorolling and nucleation of fine coherent Guinier–Preston (GP) zones of Al2Cu precipitates during postcryoroll aging has led to about 100% increment in the wear resistance of the material. Tensile test results proved that the synergetic effect of cryorolling and aging treatment led to 53% increment in strength (557 MPa) without compromising the material's ductility (22.5%). A detailed investigation on the various mechanisms responsible for the enhanced wear resistance and improved mechanical performance is presented based on the microstructural evidence.
Citations
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Journal ArticleDOI
TL;DR: In this article, the effect of microstructural modification on different wear mechanisms namely: abrasive, oxidation, delamination and melt wear was investigated under a set of processing parameters and the inherent mechanisms of all the four types of wear behavior are established for all the material conditions.

32 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of varying sizes of SiC ceramic reinforcement (coarse (12μm), fine (1μm) and nano (45 nm) in establishing the wear mechanisms and the wear mechanism maps of ultrafine grained (UFG) AA6063/4 wt%SiC composites was described.

27 citations

Journal ArticleDOI
13 Oct 2020
TL;DR: In this article, the primary synthesis and secondary treatment of Aluminium matrix composites (AMCs) has been reviewed and the renewed quest for component materials with high strength-to-weight ratio, u...
Abstract: In this paper, the primary synthesis and secondary treatment of Aluminium matrix composites (AMCs) has been reviewed. The renewed quest for component materials with high strength-to-weight ratio, u...

20 citations

Journal ArticleDOI
TL;DR: In this paper, the mechanical properties and microstructure of Al-Cu-Li alloy sheets subjected to cryorolling (−100 °C, −190 °C) or hot rolling (400 °C), and subsequent aging at 160 °C for different times were investigated.
Abstract: The mechanical properties and microstructure of Al-Cu-Li alloy sheets subjected to cryorolling (−100 °C, −190 °C) or hot rolling (400 °C) and subsequent aging at 160 °C for different times were investigated. The dynamic precipitation and dislocation characterizations were examined via transmission electron microscopy and X-ray diffraction. The grain morphologies and the fracture-surface morphologies were studied via optical microscopy and scanning electron microscopy. Samples subjected to cryorolling followed by aging exhibited relatively high dislocation densities and a large number of precipitates compared with hot-rolled samples. The samples cryorolled at −190 °C and then aged for 15 h presented the highest ultimate tensile strength (586 MPa), while the alloy processed via hot rolling followed by 10 h aging exhibited the highest uniform elongation rate (11.5%). The size of precipitates increased with the aging time, which has significant effects on the interaction mechanism between dislocations and precipitates. Bowing is the main interaction method between the deformation-induced dislocations and coarsened precipitates during tensile tests, leading to the decline of the mechanical properties of the alloy during overaging. These interesting findings can provide significant insights into the development of materials possessing both excellent strength and high ductility.

9 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the authors used a Geiger counter spectrometer to measure the changes in intensity distribution in the spectra of cold worked aluminium and wolfram and found that the line breadths may be attributed to simultaneous small particle size and strain broadening, the latter predominating at the higher Bragg angles.

7,802 citations

Journal ArticleDOI
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.
Abstract: The interpretation of certain phenomena occuring at nominally flat surfaces in stationary or sliding contact is dependent on the assumed distribution of the real area of contact between the surfaces. Since there is little direct evidence on which to base an estimate of this distribution, the approach used is to set up a simple model and compare the deduced theory (e.g., the deduced dependence of the experimental observables on the load) with the experimental evidence. The main conclusions are as follows. (a) The electrical contact resistance depends on the model used to represent the surfaces; the most realistic model is one in which increasing the load increases both the number and size of the contact areas. (b) In general, mechanical wear should also depend on the model. However, in wear experiments showing the simplest behavior, the wear rate is proportional to the load, and these results can be explained by assuming removal of lumps at contact areas formed by plastic deformation; moreover, this particular deduction is independent of the assumed model. This suggests that a basic assumption of previous theories, that increasing the load increases the number of contacts without affecting their average size, is redundant.

5,771 citations

Journal ArticleDOI
31 Oct 2002-Nature
TL;DR: A thermomechanical treatment of Cu is described that results in a bimodal grain size distribution, with micrometre-sized grains embedded inside a matrix of nanocrystalline and ultrafine (<300 nm) grains, which impart high strength, as expected from an extrapolation of the Hall–Petch relationship.
Abstract: Nanocrystalline metals--with grain sizes of less than 100 nm--have strengths exceeding those of coarse-grained and even alloyed metals, and are thus expected to have many applications. For example, pure nanocrystalline Cu (refs 1-7) has a yield strength in excess of 400 MPa, which is six times higher than that of coarse-grained Cu. But nanocrystalline materials often exhibit low tensile ductility at room temperature, which limits their practical utility. The elongation to failure is typically less than a few per cent; the regime of uniform deformation is even smaller. Here we describe a thermomechanical treatment of Cu that results in a bimodal grain size distribution, with micrometre-sized grains embedded inside a matrix of nanocrystalline and ultrafine (<300 nm) grains. The matrix grains impart high strength, as expected from an extrapolation of the Hall-Petch relationship. Meanwhile, the inhomogeneous microstructure induces strain hardening mechanisms that stabilize the tensile deformation, leading to a high tensile ductility--65% elongation to failure, and 30% uniform elongation. We expect that these results will have implications in the development of tough nanostructured metals for forming operations and high-performance structural applications including microelectromechanical and biomedical systems.

2,531 citations

Journal ArticleDOI
TL;DR: In this paper, the authors cover the latest developments in enhanced mechanical properties of aluminium alloys, and high performance joining techniques, including laser beam welding and friction stir welding, and compare them with the traditional aluminum alloys.

1,726 citations