Influence of severe plastic deformation at cryogenic temperature on grain refinement and softening of pure metals: Investigation using high-pressure torsion

Edalati, Kaveh; Cubero-Sesín, Jorge M.; Alhamidi, Ali; Mohamed, Intan Fadhlina; Horita, Zenji

doi:10.1016/j.msea.2014.06.084

Cited by 103 publications

(81 citation statements)

References 42 publications

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“…This hardness level (~140 Hv) is a well-known value of the saturated hardness after SPD of copper at room temperature. [10] The CTD sample exhibited a much greater hardness (~170 Hv, more thañ 30 Hv) than did the RTD sample (~145 Hv). Such an increase in hardness in the low-temperature compressed samples could be attributed to a suppression of defect recovery and to smaller grains.…”

Section: Resultsmentioning

confidence: 88%

“…The difference in hardness between the RTD and CTD samples is similar to the difference in saturated hardness of HPT copper processed at room and at cryogenic temperatures. [10] The OM microstructures of the RTD and CTD samples are shown in Figures 3(a) and (b), respectively. Two upper images in Figures 3(a) and (b) were obtained at low magnification and the others from high-magnification observation.…”

Section: Resultsmentioning

confidence: 99%

“…Deformation of copper at cryogenic temperature with large strain is not the only requirement for micro/ ultrafine bi-modal structure. Edalati et al [10] presented a very unstable microstructure for both high purity (99.99999 pct) and commercial purity (99.99 pct) copper, which finally became a fully recrystallized microstructure at room temperature, 200 minutes after the cryogenic HPT process. Contrary to this case, relatively stable microstructure was maintained in our CTD sample.…”

Section: Resultsmentioning

confidence: 99%

“…[31] The second involves relatively stable twin boundaries generated during deformation under conditions of cryogenic temperature, high strain rate, and moderate strain. [10,32] A proper amount of strain (~1.7) and stable twin boundaries, which maintain tolerable misorientations, also suppress the activation of full recrystallization during diffusion-related recrystallization.…”

Section: Resultsmentioning

confidence: 99%

“…In order to further decrease the lower bound of the grain size, and to expand the microstructural window of SPD-processed materials, many researchers have been interested in controlling processing parameters, such as strain rate and temperature, at extreme levels. [6][7][8][9][10] The simultaneous effects of strain rate and temperature on microstructural evolution during plastic deformation are generally expressed by the Zener-Hollomon parameter, Z, as follows:…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Bi-modal Structure of Copper via Room-Temperature Partial Recrystallization After Cryogenic Dynamic Compression

Ahn

Lee

Kang

et al. 2016

Metall Mater Trans A

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PURE copper was compressed at high strain rates (over~3 9 10 3 s À1 ) under liquid nitrogen. This deformation resulted in bi-modal microstructures of ultrafine grains and abnormally grown micro grains, and in greater hardness (by~30 Hv) than room-temperature, dynamically deformed copper. This bi-modal microstructure is attributable to partial recrystallization at room temperature, activated by high-energy states and by twins generated at high ZenerHollomon parameter conditions. This result demonstrates a new approach for producing bi-modally structured materials.

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Section: Resultsmentioning

confidence: 88%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Bi-modal Structure of Copper via Room-Temperature Partial Recrystallization After Cryogenic Dynamic Compression

Ahn

Lee

Kang

et al. 2016

Metall Mater Trans A

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Processing Magnesium and Its Alloys by High‐Pressure Torsion: An Overview

Figueiredo

Langdon

2018

Adv Eng Mater

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Magnesium and its alloys have attracted significant attention in recent years because they display high strength-to-density ratios, they are biodegradable and they provide a potential for hydrogen storage. Many investigations have examined the effect of high-pressure torsion processing on the microstructures and properties of these materials so that numerous reports are now available. This overview provides a summary of the observations reported to date on the structure and mechanical property evolution including the nature of grain refinement, the grain boundary misorientation distributions, texture evolution, and the minimum grain size. For convenience, the mechanical properties are separated into hardness, tensile behavior, and superplastic properties. It is shown that the mechanism of grain refinement differs from other metallic materials processed by severe plastic deformation but high strength may be achieved in magnesium alloys and exceptional ductility in pure magnesium. Hydrogen storage and corrosion behavior are also examined together with a discussion of recent attempts to produce magnesium-based nanocomposites through processing by high-pressure torsion.

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Effect of Long‐Term Storage on Microstructure and Microhardness Stability in OFHC Copper Processed by High‐Pressure Torsion

et al. 2019

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Tests are conducted to evaluate the effect of long-term storage on the microstructure and microhardness of an oxygen-free high conductivity (OFHC) copper after processing by high-pressure torsion (HPT) for various numbers of revolutions at ambient temperature. Results are presented for samples subjected to storage at room temperature through periods of either 1.25 or 7 years. The results show that an increase in storage time leads to a coarsening of the ultrafine-grained structure produced by HPT processing and a corresponding decrease in the microhardess where this is associated with the occurrence of recrystallization and grain growth. Plots of hardness against equivalent strain reveal a three-stage behavior with much lower hardness values over a range of equivalent strains of ~2-8. This behavior is similar after both storage periods but the hardness values are lower and the grain sizes are larger after II storage for the longer time. The results demonstrate that long-term storage has a significantly detrimental effect on the microstructure and hardness of ultrafine-grained OFHC Cu

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Influence of severe plastic deformation at cryogenic temperature on grain refinement and softening of pure metals: Investigation using high-pressure torsion

Cited by 103 publications

References 42 publications

Bi-modal Structure of Copper via Room-Temperature Partial Recrystallization After Cryogenic Dynamic Compression

Bi-modal Structure of Copper via Room-Temperature Partial Recrystallization After Cryogenic Dynamic Compression

Processing Magnesium and Its Alloys by High‐Pressure Torsion: An Overview

Effect of Long‐Term Storage on Microstructure and Microhardness Stability in OFHC Copper Processed by High‐Pressure Torsion

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