Bulk Nanostructured Multiphase Ferrous and Nonferrous Alloys

Добаткин, С. В.; Sauvage, Xavier

doi:10.1002/9783527626892.ch26

Cited by 3 publications

(2 citation statements)

References 134 publications

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“…The widely known methods of SPD, in contrast to traditional methods of metal forming, are aimed to form a microstructure with a grain size less than one micron, changing the phase composition and mechanical properties throughout the volume of the material being deformed [1][2][3][4][5][6][7][8][9][10] . As a rule, this leads to a significant increase in the strength characteristics of deformable materials by 1.5 -3 times.…”

Section: Introductionmentioning

confidence: 99%

Gradient of strength and microstructure after deformation by free torsion of metal bar

Zhilyaev

Рааб

et al. 2019

Lett. Mater.

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The article presents the results of the study and analysis of the structure, properties and deformation parameters of a longlength bar of a circular cross-section from grade 10 steel obtained using severe plastic deformation (SPD) by free torsion at a temperature of 600°C. Using computer simulations with Deform 3D software, the stress-strain state of the samples, including the distribution of accumulated strain, average stresses, and thermal field, are investigated. A physical experiment was carried out, the structure parameters and microhardness in the longitudinal section of the samples after deformation were investigated. It was shown that the free-torsion SPD method provided a non-uniform accumulation of ultrahigh strains up to 6 in long-length metal bars of a circular cross-section, the formation of a gradient type structure with a mean grain size from 1 to 7 μm and with a gradient in mechanical properties. The effect of localization of deformation during uniform torsion of the workpiece was revealed, at the same time, the temperature of the bar during severe plastic deformation increased up to 230°C. EBSD analysis revealed a gradient structure of steel specimens with a mean grain size of about 1 µm near the surface area and ~5 µm near the central area.

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Section: Introductionmentioning

confidence: 99%

Gradient of strength and microstructure after deformation by free torsion of metal bar

Zhilyaev

Рааб

et al. 2019

Lett. Mater.

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show abstract

“…Theoretically, if the second-phase nanoparticles are highly dispersed in composite materials, the strong interaction between dislocation lines and the nanoparticles can almost completely block the movements of dislocations, leading to a huge improvement of mechanical properties. 17,18 To achieve good dispersion of the nanoparticles, powder suspension has to be physically maintained in the solution by vigorous agitation, air injection, ultrasonic vibration, or adding surfactants. However, it is always difficult for nanoparticles to achieve good suspension because they have very large surface areas.…”

mentioning

confidence: 99%

Synthesis of Nanostructured Ni–TiO[sub 2] Composite Coatings by Sol-Enhanced Electroplating

Chen

Gao

2010

J. Electrochem. Soc.

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A Ni-TiO 2 composite film was prepared by electrodeposition containing Ti precursor sol ͑sol-enhanced deposition͒. The electrochemical process, microstructures, and properties of the sol-enhanced and traditional composite coatings were studied and compared. The sol-enhanced Ni-TiO 2 composite coating possessed a smooth surface and a compact microstructure and showed higher mechanical properties ͑430 HV 100 ͒ compared with the traditional coatings ͑360 HV 100 ͒. It is believed that the strengthening effects resulted from the high dispersion of TiO 2 nanoparticles. The sol added coatings also showed slower growth of Ni grains along the ͓220͔ direction but did not change the orientation. It is suggested that the sol addition reduced the thickness of the diffusion layer and increased the limited current density. Therefore, the polarization control in the sol-enhanced process changed from the traditional concentration polarization to electrochemical polarization, avoiding the formation of loose and dendritic structures at high current density.Since the Watts solution was formulated in 1916, Ni electroplating has been a commercially important and versatile surface coating/ finishing process. 1,2 Ni or Ni alloys have been widely deposited on the surfaces of working parts to improve their corrosion and wear resistance or modify magnetic and other properties. 2-4 To achieve better properties, the electrodeposited Ni or Ni alloys were modified by codepositing second-phase particles in the matrix called composite coatings. The traditional composite coating method is a solid particle mixing process: The second-phase particles are suspended in the Ni electroplating solution, and then both the particles and the Ni ions codeposit onto the specimens/parts to form composite coatings. 4 The Ni-based composite coatings were fabricated earlier from suspensions of relatively large ͑typically micrometer level͒ particles of carbides, 5 oxides, 6 diamond, 7 and Teflon. 8,9 More recently, there has been increasing emphasis on codepositing Ni ions and superfine or nanosized particles to synthesize a new structure, i.e., nanocomposite coatings. The superfine/nanoparticles are dispersed into the Ni matrix, providing significantly improved properties, such as hardness and wear resistance. [10][11][12][13][14] The strengthening mechanisms for nanocomposite coatings can be interpreted based on the dislocation model such as the Orowan theory. 15 In this theory, the critical condition for a dislocation to bypass the particles in its glide plane is to bend the dislocation to a semicircle between the particles. The dislocation with its dipoles annihilated can move forward while dislocation loops are left behind, surrounding each particle. 15-17 Orowan's criterion indicates that mechanical properties of composite coatings increase with both decreasing mean planar interparticle spacing and particle size.Based on the above theory, the incorporation of second-phase superfine/nanoparticles can be much more effective than microsized particles in reinfor...

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Effect of Severe Plastic Deformation on the Properties and Structural Developments of high purity Al and Al-Cu-Mg-Zr Aluminium Alloy

Kvačkaj¹,

Bidulská²,

Kočiško³

et al. 2011

Aluminium Alloys, Theory and Applications

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Bulk Nanostructured Multiphase Ferrous and Nonferrous Alloys

Cited by 3 publications

References 134 publications

Gradient of strength and microstructure after deformation by free torsion of metal bar

Gradient of strength and microstructure after deformation by free torsion of metal bar

Synthesis of Nanostructured Ni–TiO[sub 2] Composite Coatings by Sol-Enhanced Electroplating

Effect of Severe Plastic Deformation on the Properties and Structural Developments of high purity Al and Al-Cu-Mg-Zr Aluminium Alloy

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