Structure and density of submicrocrystalline titanium produced by severe plastic deformation

Салищев, Г. А.; Galeyev, R.M.; Malysheva, S. P.; Myshlyaev, М. M.

doi:10.1016/s0965-9773(99)00195-6

Cited by 23 publications

(12 citation statements)

References 12 publications

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“…3 Room temperature hardness against grain size for CP Ti from Refs. [6,7] and current investigation relatively high. The difference of H 0 (156.5 H v *123.4 H v ) might be due to a difference in the impurity content in Ti.…”

Section: Resultsmentioning

confidence: 54%

Microstructures and mechanical properties of ultrafine grained pure Ti produced by severe plastic deformation

2010

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Microstructure evolution and mechanical behavior of ultrafine grained (UFG) commercially pure Ti produced by equal channel angular pressing (ECAP) were investigated. Repetitive pressings of the same sample were performed to six passes at 683 K, using the procedure designated as route B c . After the sixth pass was finished, recrystallized grains were observed as similar as the fourth pass. The average size of the recrystallized grains was approximately 0.3 lm. The hardness value (H v ) continuously increases with decreasing grain size. The H v values are in good agreement with the other experimental data of Ti produced by severe plastic deformation processes. The similar slop k H suggests that these microstructures have similar density of dislocations in the grains produced by the severe plastic deformation processes such as torsion straining, multiple forging, and ECAP. The grain size dependence of k y in the present samples is 7.9 MPa ffiffiffi ffi m p. After six-pass ECAP, the ultimate tensile strength was increased by 60%. This is most likely due to considerable grain refinement through severe deformation by ECAP. The standard Hall-Petch relation for yield strength and hardness in the ECAPed Ti implies that the ECAPed Ti samples have similar texture and that the effect of grain size on strength may prevail over the effect of texture on the strength in Ti.

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Section: Resultsmentioning

confidence: 54%

Microstructures and mechanical properties of ultrafine grained pure Ti produced by severe plastic deformation

2010

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“…2 shows that the H-P relation is valid down to 9 nm in commercially pure Ti where the yield stress [YS] is taken as 1/3 rd of the measured microhardness. [76] Based on five investigations, [76][77][78][79][80] the average H-P slope is ~13 MPa mm ½ . A combination of HPT at 5.0 GPa for 10 rotations followed by annealing at 523-273 K (250-300°C) gives more than 1200 MPa in pure Ti with a grain size of 120 nm and this is comparable to the reported strengths of Ti alloys.…”

Section: The Hall-petch Relationship For Ufg Materialsmentioning

confidence: 99%

“…Microhardness-grain size relation in commercial purity Ti; [76] the H-P relationship holds down to 9 nm using experimental data. [76,80] Figure 3. The H-P relationship for Ti; [81] grades 1 to 4 denote increasing orders of impurities for Fe, N and O and using experimental data.…”

Section: Figure Captionsmentioning

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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“…The relationship between the microhardness and the grain size of titanium, in the form of the Hall-Petch plot, is shown in Fig. 7 together with the literature data [14][15][16][17]. The grain size/yield stress relationship was discussed in our earlier study [8].…”

Section: Contributedmentioning

confidence: 84%

Bulk nanostructured titanium fabricated by hydrostatic extrusion

Topolski¹,

Garbacz

Pachla

et al. 2010

Phys. Status Solidi (c)

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The paper is concerned with the use of Hydrostatic Extrusion (HE), which is one of the methods of Severe Plastic Deformation (SPD), for grain refinement of titanium grade 2. Titanium in the form of rods was subjected to multi‐stage extrusion. The aim was to optimize the HE process so as to obtain nanostructured titanium rods. The results show that it is possible to produce nanostructured Ti rods of a diameter suitable for industrial applications. The refinement to nano‐sized grains is accompanied by a significant improvement of mechanical properties. The tensile strength of more than 1000MPa was achieved and the hardness increase exceeded 50%. This study was also concerned with the problem of up‐scaling the dimensions of nano‐refined components produced by HE. The basic condition for HE to yield nanostructured Ti is that an appropriately high accumulated strain should be applied (ε > 3). The results demonstrate that, by using HE, we can produce nano‐Ti rods with diameters amounting to ∅︁8mm. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Structure and density of submicrocrystalline titanium produced by severe plastic deformation

Cited by 23 publications

References 12 publications

Microstructures and mechanical properties of ultrafine grained pure Ti produced by severe plastic deformation

Microstructures and mechanical properties of ultrafine grained pure Ti produced by severe plastic deformation

The Strength–Grain Size Relationship in Ultrafine-Grained Metals

Bulk nanostructured titanium fabricated by hydrostatic extrusion

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