Ultrafine-grain metals by severe plastic deformation

Tóth, László; Gu, Chengfan

doi:10.1016/j.matchar.2014.02.003

Cited by 226 publications

(110 citation statements)

References 56 publications

Supporting

Mentioning

103

Contrasting

Unclassified

Order By: Relevance

“…The occurrence of such saturation of grain size is thought to be due to the microstructure becoming saturated with lattice defects, primarily in the form of vacancies and dislocations, causing additional plastic deformation to produce dynamic recovery in which the work of mechanical deformation is effectively transformed into heat rather than additional lattice defects [7,37]. It is well known that grain boundaries can act as dislocation sinks [9,37] and when the grains are refined to nano size at equivalent strains above ~6.0, a balance is established between generation of dislocations by HPT and absorption of dislocations at grain boundaries. As a result, the hardness reaches a saturation state.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Evolution of microstructure and mechanical properties of an as-cast Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr alloy processed by high pressure torsion

Sun

Qiao

et al. 2017

Materials Science and Engineering: A

View full text Add to dashboard Cite

Abstract:The novel Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr alloy with high content of rare earth elements has been processed successfully by high pressure torsion (HPT) starting from an as-cast condition. HPT processing was conducted at room temperature for a range of turns from 1/8 to 16, and the evolutions of microstructure and microhardness were investigated.The average grain size decreases from ~85 μm in the as-cast condition to ~55 nm when the equivalent strain reaches ~6.0, and remains almost constant on further strain increase. Meanwhile, the coarse netlike Mg3(Gd,Y) second phase structures are gradually broken into fine dispersed particles and the dislocation density increases. The microhardness of the alloy increases with increasing strain, and when the equivalent strain reaches ~6.0, the microhardness reaches a saturated value of about 115 HV, which is higher than that obtained by conventional extrusion / rolling of this alloy. The full range of possible mechanisms of hardening are analysed and this reveals that hardening is primarily due to the pronounced grain refinement, which is substantially 2 stronger than that for HPT-processed conventional Mg alloys, and to the homogeneously distributed fine second phase particles and the high dislocation density.

show abstract

Section: Discussionmentioning

confidence: 99%

“…HPT has the potential for achieving greater grain refinement than other SPD procedures. Application of quasihydrostatic pressure in HPT prevents cracking, so HPT can be used to deform Mg alloys at low temperature to produce bulk ultrafine-grained Mg alloys [8,9]. However, a full analysis of strengthening mechanisms, e.g.…”

Section: Introductionmentioning

confidence: 99%

Evolution of microstructure and mechanical properties of an as-cast Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr alloy processed by high pressure torsion

Sun

Qiao

et al. 2017

Materials Science and Engineering: A

View full text Add to dashboard Cite

show abstract

“…reported that the ductility is improved in fine -grained magnesium AZ31 (Mg -3%Al -1%Zn) alloys due to the activity of non -basal slip, grain boundary sliding (GBS) and recovery at high strained region. That is, grain refinement improves both strength and ductility in magnesium alloys [1].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, strength of the conventional wrought magnesium alloys is lower than that of aluminium alloys, which prevents application to structural component that requires high strength. It has been reported that the strength of magnesium alloys is improved by means of grain refinement according to the Hall -Petch relation (1). Also, recent research reveals that high ductility can be obtained by structure control such as grain refinement and texture control even in magnesium alloys.…”

Section: Introductionmentioning

confidence: 99%

Grain Refinement of Extruded AZ31 Magnesium Alloy by Ecap Process

Hilšer¹,

Rusz²,

Krejčí³

et al. 2017

TransVSBms

View full text Add to dashboard Cite

Extruded Mg -3%Al -1% Zn (AZ31) magnesium alloy was subjected to ECAP (Equal Channel Angular Pressing) processing at 523 K (250 °C). At the processing temperature of 523 K, fine grains with the average grain size of 2 -3 µm are formed as a result of dynamic recrystallization originated by fine Mg17Al12 (γ) phase particles having 200 nm diameter dynamically -precipitated during ECAP processing. Microstructural evolution during ECAP was studied systematically using optical microscope and transmission electron microscope. KeywordsAZ31, EX -ECAP, Optical microscopy, Transmission electron microscopy. AbstraktProtlačená hořčíková slitina Mg -3%Al -1%Zn (AZ31) byla zpracována procesem ECAP (úhlové protlačování rovnostranným kanálem) realizovaného při teplotě 523 K (250 °C). Při teplotě 523 K bylo dosaženo zjemnění průměrné velikosti zrna 2 -3 µm, které bylo dosaženo dynamickou rekrystalizací jemné γ faze Mg17Al12 s průměrnou velikostí 200 nm. Vývoj mikrostruktury během ECAP byl systematicky studován na optickém mikroskopu a využitím transmisní elektronové mikroskopie. Klíčová slovaAZ31, EX -ECAP, Optická mikroskopie, Transmisní elektronová mikroskopie.

show abstract

“…Clinical practice and many scientific reports show a high level of biocompatibility of commercially pure (CP) Ti (Sidambe, 2014). However, its mechanical characteristics can be improved by severe plastic deformation (SPD) (Toth and Gu, 2014). Interestingly, the proliferation of fibroblastic cells and stem cells on the surface of nanostructured Ti processed by SPD has been shown to be promoted by grain refinement (Valiev et al, 2016).…”

mentioning

confidence: 99%

Thin Bioactive Zn Substituted Hydroxyapatite Coating Deposited on Ultrafine-Grained Titanium Substrate: Structure Analysis

et al. 2018

View full text Add to dashboard Cite

Nanocrystalline Zn-substituted hydroxyapatite coatings were deposited by radiofrequency magnetron sputtering on the surface of ultrafine-grained titanium substrates. Cross-section transmission electron microscopy provided information about the morphology and texture of the thin film while in-column energy dispersive X-ray analysis confirmed the presence of Zn in the coating. The Zn-substituted hydroxyapatite coating was formed by an equiaxed polycrystalline grain structure. Effect of substrate crystallinity on the structure of deposited coating is discussed. An amorphous TiO2 sublayer of 8-nm thickness was detected in the interface between the polycrystalline coating and the Ti substrate. Its appearance in the amorphous state is attributed to prior to deposition etching of the substrate and subsequent condensation of oxygen-containing species sputtered from the target. This layer contributes to the high coating-to-substrate adhesion. The major P-O vibrational modes of high intensity were detected by Raman spectroscopy. The Zn-substituted hydroxyapatite could be a material of choice when antibacterial osteoconductive coating with a possibility of withstanding mechanical stress during implantation and service is needed.

show abstract

Ultrafine-grain metals by severe plastic deformation

Cited by 226 publications

References 56 publications

Evolution of microstructure and mechanical properties of an as-cast Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr alloy processed by high pressure torsion

Evolution of microstructure and mechanical properties of an as-cast Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr alloy processed by high pressure torsion

Grain Refinement of Extruded AZ31 Magnesium Alloy by Ecap Process

Thin Bioactive Zn Substituted Hydroxyapatite Coating Deposited on Ultrafine-Grained Titanium Substrate: Structure Analysis

Contact Info

Product

Resources

About