A critical examination of pure tantalum processed by high-pressure torsion

Maury, Nicolas; Zhang, Nian Xian; Huang, Yi; Zhilyaev, Alexander P.; Langdon, Terence G.

doi:10.1016/j.msea.2015.04.053

Cited by 48 publications

(27 citation statements)

References 59 publications

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“…6 show there is an increase from an initial value of ~260 to ~920 MPa after 10 turns but with a corresponding reduction in elongation from ~79% to ~29%. This strength and ductility paradox matches other reports for the HPT processing of an Al-1% Mg alloy [30] and pure tantalum [31] where it was shown that short-term annealing after HPT processing produced a small reduction in strength but a significant increase in ductility.…”

Section: Strength and Ductility Development During Hpt Processing Andsupporting

confidence: 91%

Achieving superior grain refinement and mechanical properties in vanadium through high-pressure torsion and subsequent short-term annealing

Huang¹,

Lemang²,

Zhang³

et al. 2016

Materials Science and Engineering: A

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Commercial purity vanadium with an initial grain size of ~27 m and a Vickers microhardness of Hv  85 was processed by high-pressure torsion (HPT) under a pressure of 6.0 GPa at room temperature through 1/2 to 10 turns. After processing through 10 turns, some samples were immediately subjected to a short-term annealing (15 min) at different temperatures from 773 to 1173 K. The microstructures developed in HPT and in HPT plus post-HPT annealing were characterized by electron backscatter diffraction (EBSD).Processing by HPT for 10 turns gave a refined grain size of ~410 nm and an increased hardness of Hv  240. Post-HPT annealing demonstrated that the ultrafine grained vanadium has good thermal stability up to at least 873 K. Tensile testing at room temperature gave an ultimate tensile strength of ~920 MPa after 10 turns of HPT with an elongation of ~29%.These results show HPT processing produces superior mechanical properties in vanadium by comparison with processing by ECAP or ECAP plus cryorolling.

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Section: Strength and Ductility Development During Hpt Processing Andsupporting

confidence: 91%

Achieving superior grain refinement and mechanical properties in vanadium through high-pressure torsion and subsequent short-term annealing

Huang¹,

Lemang²,

Zhang³

et al. 2016

Materials Science and Engineering: A

Self Cite

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show abstract

“…In addition, annealing may also decrease the dislocation density in the grain interior of an SPD-processed material, thereby facilitating effective dislocation storage, and an enhanced storage capability may increase the strain hardening leading to increased ductility in these materials. Subsequently, similar results were reported for Cu processed by ECAP [37], Ti processed by ECAP and drawing [38], Ti processed by ECAP-Conform and drawing [39], and pure Ta processed by HPT [40].…”

Section: Effect Of a Short-term Anneal After Processingsupporting

confidence: 78%

Review: Overcoming the paradox of strength and ductility in ultrafine-grained materials at low temperatures

2015

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Ultrafine-grained (UFG) materials with grain sizes in the submicrometer or nanometer range may be prepared through the application of severe plastic deformation (SPD) to bulk coarse-grained solids. These materials generally exhibit high strength but only very limited ductility in low-temperature testing, thereby giving rise to the so-called paradox of strength and ductility. This paradox is examined and a new quantitative diagram is presented which permits the easy insertion of experimental data. It is shown that relatively simple procedures are available for achieving both high strength and high ductility in UFG materials including processing the material to a very high strain and/or applying a very short-term anneal immediately after the SPD processing. Significant evidence is now available demonstrating the occurrence of grain boundary sliding in these materials at low temperatures, where this is attributed to the presence of non-equilibrium grain boundaries and the occurrence of enhanced diffusion along these boundaries.

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“…In addition, short-term annealing reduces the dislocation density in the grain interior of the UFG material after SPD so that the dislocation storage capability may increase and thus the strain hardening capability is enhanced wand this leads to the possibility of high ductility in the SPD-processed material. There are several recent reports demonstrating the significance of PDA on mechanical properties at RT of HPT-processed materials [51][52][53][54]. Thus, considering the present nanoindentation results reporting a significant enhancement in the strain rate sensitivity after PDA, the MMNC in the Al-Mg system produced by HPT has a great potential for demonstrating both high hardness and superior ductility.…”

Section: The Improvement In Micro-mechanical Response By Pdasupporting

confidence: 57%

Micro-mechanical and tribological properties of aluminum-magnesium nanocomposites processed by high-pressure torsion

Han

Lee

Jang

et al. 2017

Materials Science and Engineering: A

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High-pressure torsion (HPT) is one of the major severe plastic deformation (SPD) procedures where bulk metals, in the shape of a disk, achieve exceptional grain refinement at ambient temperatures. HPT has been applied for the consolidation of metallic powders and the bonding of machining chips whereas there are very limited reports examining the application of HPT for the production of new metal systems and the formation of nanocomposites. Accordingly, this investigation was initiated to evaluate the potential for the formation of a metal matrix nanocomposite (MMNC) by processing two commercial metal disks of an Al-1050 alloy and a ZK60 magnesium alloy through HPT under 6.0 GPa for 20 turns at room temperature. Evolutions in microstructure, mechanical properties including hardness and plasticity and the tribological properties were examined in the MMNC region of the processed Al-Mg system. The significance of post-deformation annealing (PDA) at 573 K for 1 hour was investigated by the change in microstructure and the enhancement in mechanical properties and wear resistance of the HPT-processed MMNC. This study demonstrates the promising feasibility of using HPT to fabricate a wide range of hybrid MMNCs from simple metals and for applying PDA for further improvement of the essential mechanical and tribological properties in the synthesized alloy systems.

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A critical examination of pure tantalum processed by high-pressure torsion

Cited by 48 publications

References 59 publications

Achieving superior grain refinement and mechanical properties in vanadium through high-pressure torsion and subsequent short-term annealing

Achieving superior grain refinement and mechanical properties in vanadium through high-pressure torsion and subsequent short-term annealing

Review: Overcoming the paradox of strength and ductility in ultrafine-grained materials at low temperatures

Micro-mechanical and tribological properties of aluminum-magnesium nanocomposites processed by high-pressure torsion

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