Thermal stability and recrystallization of nanocrystalline Ti produced by cryogenic milling

Sun, Fusheng; Zúñiga, Alejandro; Rojas, Paula; Lavernia, Enrique J.

doi:10.1007/bf02586127

Cited by 43 publications

(35 citation statements)

References 37 publications

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“…[43][44][45] Grain boundaries and dislocations accommodate solute atoms more readily as a result of their higher surface energy. [46,47] The results are also consistent with earlier studies on cryomilled Ti, [17] Al, [48] and Ni [49] alloys, as well as general literature on the Ti structure. [2,12,42] The average grain size of 8 hours of cryomilled powders was calculated to be 19 nm from the XRD peak broadening data using the single-line-approximation analysis developed by De Keijser et al [50] Approximating the grain size broadening profiles by a Cauchy function, the grain size (D) can be estimated from each diffraction peak with diffraction angle h by:…”

Section: A Cryomilled Powderssupporting

confidence: 91%

“…Despite the reported thermal stability of cryomilled CP-Ti powders, [17] as documented in the literature, experiments were conducted in the current study to investigate the effects of carbon black used as PCA. The calculated grain sizes from XRD peak broadening profiles for corresponding annealing temperatures were plotted in Figure 1.…”

Section: A Cryomilled Powdersmentioning

confidence: 99%

“…In roomtemperature tensile tests, a YS of 840 MPa, a UTS of 902 MPa, and an elongation to failure value of 27.5 pct were measured for these samples. More detailed information related to cryomilled Ti powders and bulk materials is available in related publications by Sun et al [16,17] and Ertorer et al [14] In view of the aforementioned results, the objective of the present work is to investigate the consolidation behavior, microstructure evolution and mechanical behavior of cryomilled CP-Ti powders consolidated via the spark plasma sintering (SPS) technique. In the last-two decades, SPS has emerged as an interesting consolidation approach given its reported ability to densify metal and ceramic powders fully in a short time interval, thereby helping retain the starting microstructure.…”

Section: Introductionmentioning

confidence: 99%

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Nanostructured Ti Consolidated via Spark Plasma Sintering

Ertörer

Topping

et al. 2010

Metall Mater Trans A

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Cryomilled nanocrystalline commercially pure (CP)-Ti powders were spark plasma sintered (SPS) using different process parameters (heating rate, temperature, pressure, and dwell time) to study densification, microstructure, and mechanical behavior. The results were rationalized on the basis of the relevant literature and experimental results, and they reveal a strong dependence on SPS parameters. An interesting finding was that the measured high ductility was accompanied by a moderate strength (yield strength [YS] = 770 MPa, ultimate tensile strength [UTS] = 840 MPa with~27 pct elongation to failure). The combinations of microstructure and mechanical response were attributed to the multistep processing at different temperature ranges as well as to the presence of interstitial solutes.

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Section: A Cryomilled Powderssupporting

confidence: 91%

Section: A Cryomilled Powdersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nanostructured Ti Consolidated via Spark Plasma Sintering

Ertörer

Topping

et al. 2010

Metall Mater Trans A

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“…[32][33][34][35][36][37] Furthermore, some other investigations also have demonstrated that the presence of grain boundary segregation, solute drag, impurities, second phase drag, pore drag and chemical ordering lead to signicantly enhanced thermal stability of nanocrystalline materials via a drag-force mechanism on the grain boundaries. [38][39][40][41][42][43][44][45][46] Similarly, in case of pure Ti, enhanced thermal stability of nanocrystalline structure was also observed in case of milled pure Ti powders, in liquid nitrogen as well as nitrogen gas mediums, after sintering at elevated temperatures. 46,47) It was demonstrated that the presence of nanosized nitrides and oxides, together with the segregation of nitrogen and oxygen, on the grain boundaries was extremely effective in achieving stable nanocrystalline structure in pure Ti.…”

Section: Microstructure Of Sintered Titanium Compactsmentioning

confidence: 82%

Three-Dimensionally Gradient and Periodic Harmonic Structure for High Performance Advanced Structural Materials

Vajpai

Ota

et al. 2016

Mater. Trans.

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Creation of a unique Harmonic Structure (HS) with controlled bimodal grain size distribution in metals and alloys is a new material design paradigm allowing the improved mechanical performance of structural materials via enhancing strength without sacri cing ductility. A well designed powder metallurgy based processing approach has been developed to create such a controlled microstructure which consists of controlled mechanical milling (MM) of powder particles to create powder particles with bimodal grain size distribution, with a peculiar coreshell structure, followed by their hot consolidation. In the present study, full density compacts with HS were prepared and the effect of such a bimodal microstructure on the mechanical properties of commercially pure Ti with hexagonal close packed (HCP) crystal structure was investigated. The HS pure Ti exhibited considerably higher strength values, without sacri cing ductility, as compared to their coarse-grained (CG) counterparts. The numerical simulation results revealed that the initial stages of deformation and strength of the HS are governed by the characteristics of the interconnected network of the strong ne-grained (FG) shell regions whereas the extent of uniform deformation and overall ductility is governed by the ductile CG core region. It was also demonstrated that the unique HS design promotes uniform deformation very ef ciently by avoiding strain localization during plastic deformation.

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“…Reduction in grain size significantly increases the strength and hence extends applications that requires reliable performance. The grain refinement mechanisms of Ti is, however, still unclear due to lack of systematic observations of deformation structures [16][17][18][19][20][21][22][23]. For example, a dynamic recrystallization (DRX) process is suggested to account for the formation of submicrosized grains [16][17][18].…”

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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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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Thermal stability and recrystallization of nanocrystalline Ti produced by cryogenic milling

Cited by 43 publications

References 37 publications

Nanostructured Ti Consolidated via Spark Plasma Sintering

Nanostructured Ti Consolidated via Spark Plasma Sintering

Three-Dimensionally Gradient and Periodic Harmonic Structure for High Performance Advanced Structural Materials

Grain refinement of pure Ti during plastic deformation

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