Nanostructured surface layer on metallic materials induced by surface mechanical attrition treatment

Lu, K.; Lü, Jian

doi:10.1016/j.msea.2003.10.261

Cited by 969 publications

(457 citation statements)

References 22 publications

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“…The SMAT set-up and procedure have been described in detail elsewhere [8,9]. The technique is based on the vibration of spherical shots using high-energy ultrasound.…”

Section: Methodsmentioning

confidence: 99%

“…Using severe plastic deformation methods such as equal channel angular pressing and high pressure torsion, the structural length scales of most metals can be easily reduced into the sub-micrometer range [1][2][3][4][5][6]. By contrast, the exploratory friction-stir experiment [7] and surface mechanical attrition treatment (SMAT) [8][9][10][11] may effectively reduce the structural length scale to 10-50 nm. Analysis of the active deformation mechanisms is a crucial step in clarifying the hardening behavior associated with grain refinement [1,2,[7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Grain refinement of pure Ti during plastic deformation

Fan

Jiang

et al. 2010

Materials Science and Engineering: A

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a b s t r a c tThe mechanism of grain refinement was studied in titanium subjected to high-rate surface mechanical attrition treatment. By cross-sectional transmission electron microscopy, the deformation structures were systematically characterized in a nanocrystalline (NC) layer of the treated surface which exhibits a grain size gradient. The microstructural evolution with increasing strain involves (1) the formation of slip bands with dislocation-free cells in their interiors, (2) nucleation and migration of high-angle grain boundaries at cell boundaries consisting of high-density tangled dislocations, leading to the formation of submicrosized grains inside the slip bands, followed by (3) the formation of subgrains and dislocation cells inside the submicrosized grains with increasing misorientations, which finally become NC grains. The mechanism of grain refinement was interpreted in terms of the classical migration dynamic recrystallization (DRX) and continuous rotation DRX, respectively, leading to submicrosized and NC grains with increasing strains at high strain rates. The cooperative grain boundary sliding is active at high strain rate, by the presence of arrays of coplanar grain boundaries.

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“…The SMAT set-up and procedure have been described in detail elsewhere [8,9]. The technique is based on the vibration of spherical shots using high-energy ultrasound.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Grain refinement of pure Ti during plastic deformation

Fan

Jiang

et al. 2010

Materials Science and Engineering: A

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“…[54] In general, ECAP produces grain sizes in the submicrometer range whereas, since a very high shear strain is imposed on the sample in HPT, it is possible to use this technique to produce grain sizes in the nanometer range. There are also several other methods of SPD processing such as equalchannel forward extrusion, [55] accumulative roll bonding, [56] surface mechanical attrition treatment [57] and repeated corrugation and straightening [58] . Methods are also available for producing metals with grain sizes in the nanometer range that do not involve SPD processing such as in the use of electroplating.…”

Section: Introductionmentioning

confidence: 99%

The Strength–Grain Size Relationship in Ultrafine-Grained Metals

Balasubramanian

Langdon

2016

Metall Mater Trans A

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Metals processed by severe plastic deformation [SPD] techniques, such as equal-channel angular pressing [ECAP] and high-pressure torsion [HPT], generally have submicrometer grain sizes. Consequently, they exhibit high strength as expected on the basis of the HallPetch [H-P] relationship. Examples of this behavior are discussed using data on Ti, Al-Mg 1 and Ni. These materials typically have grain size above ~50 nm where softening is not expected. An increase in strength is usually accompanied by a decrease in ductility. High strength and ductility can be achieved simultaneously by imposing high strains to give both ultrafine grain sizes and a high fraction of high-angle grain boundaries. An example is presented for a cast Al-7% Si alloy processed by HPT. In some cases, SPD may produce a fine grain size but also lead to a weakening due to microstructural changes as in ECAP of an Al-7034 alloy and HPT of Zn-22% Al. In SPD-processed materials, grain boundary segregation and nanostructural features are present which may lead to higher strengths than those predicted by the H-P relationship in some alloys having nano grain sizes.

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“…SMAT has been shown to increase compressive residual stresses at the surface much better than other surface treatments including shot peening and deep rolling (Burrow et al, 2004). SMAT also results in better refinement of nanostructured surface layer due to the utilization of bigger and spherical smooth balls with lower velocity compared to shot peening as reviewed by Lu et al (Lu and Lu, 2004). Study by Huang R et al showed that SMAT can help the formation of more stable and much thicker passive protection films on the nanograined structure (Huang and Han, 2013).…”

Section: Discussionmentioning

confidence: 99%

“…Study by Huang R et al showed that SMAT can help the formation of more stable and much thicker passive protection films on the nanograined structure (Huang and Han, 2013). In addition, SMAT-treatment can enhance subsurface hardness and improve surface morphology, roughness, and wettability that might not be achieved by conventional surface treatments such as shot peening (Lu and Lu, 2004;Arifvianto et al, 2011). …”

Section: Discussionmentioning

confidence: 99%