Dispersion Hardening of Cu&amp;ndash;Al&amp;ndash;Ti Alloys by Internal Oxidation

Takahashi, Terüo; Hashimoto, Yasuhiko; Omori, Shinichiro; Kôyama, Kôichirô

doi:10.2320/matertrans1960.26.271

Cited by 18 publications

(4 citation statements)

References 18 publications

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“…Although the positive role of Ti doping in Cu‐Al 2 O 3 composites is confirmed previously, [ 14,23 ] the mechanisms are still poor. Recent studies by TEM characterization with high resolution and density functional calculations reveal the formation complex oxides and the modification of matrix/particle interfacial energy.…”

Section: Discussion and Outlookmentioning

confidence: 79%

Factors Affecting the Coarsening and Agglomeration of Alumina Particles in Cu–Al₂O₃ Composites Prepared with Internal Oxidation

2021

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In future fusion reactors, the heat sink materials of divertor components have to withstand very high heat fluxes and energetic neutron irradiation, and many restrictions therefore should be satisfied, for example, mechanical properties, thermal behavior, stability under irradiation as well as availability. [1,2] These factors indeed rule out many materials categories, while Cu alloys exhibit the highest potential particularly because of the high thermal conductivity of pure base metal, [3] even though the thermal conductivity may be impaired when small amount of elements are alloyed to improve the strength. [4] Secondary phase strengthening is the most suitable route to compromise all these requirements among all the strengthening strategies, and CuCrZr is one of the mature precipitation hardened Cu alloys investigated for heat sink applications and has already been selected for the use in international thermal-nuclear experimental reactor (ITER). [5,6] However, the inadequate stability of strengthening phases in CuCrZr at elevated temperatures or under irradiation restricts its applications in future fusion reactors. An alumina dispersion strengthened Cu (DS-Cu) alloy, AL-25, has been investigated widely and considered for heat sink applications over 20 years. [7] AL-25 indeed exhibits superior irradiation resistance than CuCrZr, [8] but it still shows some drawbacks regarding mechanical properties at elevated temperatures and fracture toughness. The microscopic characteristics, for example, size, shape, number density, distribution, and interfacial structures, of nano-sized oxides therefore should be further modified to meet the requirements of demonstration reactor (DEMO) as they are the main source of beneficial properties of DS-Cu. Recently, many efforts have been devoted to the use of novel oxides, for example, Y 2 O 3 , or alternative fabricating routes, for example, mechanical alloying. [9][10][11] But traditional internal oxidation is still an attractive fabricating route because of its inherent merits such as reduced contamination and capability of mass production as well as the well-established baseline from the Cu-Al 2 O 3 system. From the viewpoint of microstructures, the alumina particles, either inter-or intragranular, in traditional Cu-Al 2 O 3 composites fabricated with internal oxidation are prone to coarsening and agglomeration, [12] which may be detrimental to ductility and irradiation resistance. Possibilities of tailoring oxides in DS-Cu through element doping, for example, Ag and Ti, have been shown already. [13,14] To tailor the nano-sized oxides intentionally, one should gain insight into the relationship between these microscopic characteristics and experimental details of internal oxidation. In this article, the origins of coarsening and agglomeration of alumina particles were uncovered through a dedicated combining investigation between powder metallurgy and Rhines-pack method, [15] and contributing factors, such as grain boundaries, diffusion distance, concentration of Al, atomizatio...

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Section: Discussion and Outlookmentioning

confidence: 79%

Factors Affecting the Coarsening and Agglomeration of Alumina Particles in Cu–Al₂O₃ Composites Prepared with Internal Oxidation

2021

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“…Many large particles at Cu grain boundaries and numerous fine particles inside the Cu grains were precipitated. The distribution of the fine oxide particles in internally oxidized Cu-Zr alloys differed from that in internally oxidized CuAl-Ti alloys (1), that is, non-uniform precipitation inside the Cu grains occurred, as shown with arrows in Fig. 5.…”

Section: Identificationmentioning

confidence: 99%

Phase and Morphology of ZrO<SUB>2</SUB> in Internally Oxidized Dilute Cu–Zr Alloys

et al. 1986

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Dilute Cu-Zr alloys containing 0.39-1.95 mass%Zr were internally oxidized in the temperature range of 973-1323 K. The phases of dispersed oxides were identified by X-ray diffractometry, and the mean oxide particle sizes were measured by transmission electron microscopy. From X-ray diffractometry of the nitric-acid-treated insoluble residues, the oxide phases precipitated by internal oxidation were monoclinic and tetragonal ZrO2. The amount ratio of monoclinic ZrO2 to the total oxide was increased with the concentration of Zr at a constant internal oxidation temperature. In the case of alloys having the same concentration of Zr, the amount of monoclinic ZrO2 presented the minimum values at about 1223-1243 K. By transmission electron microscopy, it was revealed that large monoclinic ZrO2 particles were precipitated at grain boundaries of Cu and fine monoclinic and tetragonal ZrO2 particles were precipitated inside the Cu grains. The mean particle size of fine precipitates in Cu grains was increased with the distance from the surface. Any difference in the mean particle size of fine ZrO2 inside the Cu grains was not observed among the alloys having different concentrations of Zr, owing to the limitation of solution of Zr into Cu.

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“…Especially it was reported that the mixture of Ti oxide with Al 2 O 3 show the possibility of decreasing oxide particle size in copper matrix 14 15 introducing mixture of various oxide in copper matrix. However it has been known as difficult to obtain uniform distribution of the particles 16 17 . For example, it was reported that solid-state mixtures of Ti with Al 2 O 3 might decrease the oxide particle sizes in a copper matrix 17 .…”

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confidence: 99%

“…However it has been known as difficult to obtain uniform distribution of the particles 16 17 . For example, it was reported that solid-state mixtures of Ti with Al 2 O 3 might decrease the oxide particle sizes in a copper matrix 17 . Differently from the previous work the key step we made in this study was to oxidize Al at high temperature (T = 980 °C) via an internal oxidation process and to control the interface energies between the oxides and the Cu matrix with extra-doped Ti.…”

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confidence: 99%

Design of exceptionally strong and conductive Cu alloys beyond the conventional speculation via the interfacial energy-controlled dispersion of γ-Al2O3 nanoparticles

Han

Kim

Kang

et al. 2015

Sci Rep

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The development of Cu-based alloys with high-mechanical properties (strength, ductility) and electrical conductivity plays a key role over a wide range of industrial applications. Successful design of the materials, however, has been rare due to the improvement of mutually exclusive properties as conventionally speculated. In this paper, we demonstrate that these contradictory material properties can be improved simultaneously if the interfacial energies of heterogeneous interfaces are carefully controlled. We uniformly disperse γ-Al2O3 nanoparticles over Cu matrix, and then we controlled atomic level morphology of the interface γ-Al2O3//Cu by adding Ti solutes. It is shown that the Ti dramatically drives the interfacial phase transformation from very irregular to homogeneous spherical morphologies resulting in substantial enhancement of the mechanical property of Cu matrix. Furthermore, the Ti removes impurities (O and Al) in the Cu matrix by forming oxides leading to recovery of the electrical conductivity of pure Cu. We validate experimental results using TEM and EDX combined with first-principles density functional theory (DFT) calculations, which all consistently poise that our materials are suitable for industrial applications.

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Dispersion Hardening of Cu–Al–Ti Alloys by Internal Oxidation

Cited by 18 publications

References 18 publications

Factors Affecting the Coarsening and Agglomeration of Alumina Particles in Cu–Al₂O₃ Composites Prepared with Internal Oxidation

Factors Affecting the Coarsening and Agglomeration of Alumina Particles in Cu–Al₂O₃ Composites Prepared with Internal Oxidation

Phase and Morphology of ZrO<SUB>2</SUB> in Internally Oxidized Dilute Cu–Zr Alloys

Design of exceptionally strong and conductive Cu alloys beyond the conventional speculation via the interfacial energy-controlled dispersion of γ-Al2O3 nanoparticles

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Dispersion Hardening of Cu&ndash;Al&ndash;Ti Alloys by Internal Oxidation

Cited by 18 publications

References 18 publications

Factors Affecting the Coarsening and Agglomeration of Alumina Particles in Cu–Al2O3 Composites Prepared with Internal Oxidation

Factors Affecting the Coarsening and Agglomeration of Alumina Particles in Cu–Al2O3 Composites Prepared with Internal Oxidation

Phase and Morphology of ZrO<SUB>2</SUB> in Internally Oxidized Dilute Cu&ndash;Zr Alloys

Design of exceptionally strong and conductive Cu alloys beyond the conventional speculation via the interfacial energy-controlled dispersion of γ-Al2O3 nanoparticles

Contact Info

Product

Resources

About

Dispersion Hardening of Cu–Al–Ti Alloys by Internal Oxidation

Factors Affecting the Coarsening and Agglomeration of Alumina Particles in Cu–Al₂O₃ Composites Prepared with Internal Oxidation

Factors Affecting the Coarsening and Agglomeration of Alumina Particles in Cu–Al₂O₃ Composites Prepared with Internal Oxidation

Phase and Morphology of ZrO<SUB>2</SUB> in Internally Oxidized Dilute Cu–Zr Alloys