The microstructural basis for the mechanical properties and electrical resistivity of nanocrystalline Cu–Al2O3

Nachum, Shay; Fleck, N.A.; Ashby, Michael F.; Colella, Alberto; Matteazzi, P.

doi:10.1016/j.msea.2010.04.070

Cited by 46 publications

(18 citation statements)

References 33 publications

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“…Yet, combining the two phases in a composite material has clear technological potential [6][7][8][9]: copper is an excellent heat and electricity conductor, in which Al 2 O 3 particles offer improved hardness and wear resistance without introducing atomscale electron scattering centers. The Cu-Al 2 O 3 system is non-reactive in high-vacuum or in oxygen-lean inert gas [4]; as a consequence Al 2 O 3 should not be degraded during processing.…”

Section: Introductionmentioning

confidence: 99%

Al2O3 particle rounding in molten copper and Cu8wt%Al

Krüger

Mortensen

2012

J Mater Sci

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We investigate processing-microstructure relationships in the production of Al 2 O 3 particle reinforced copper composites by solidification processing. We show that during production of the composites by gas-pressure infiltration of packed Al 2 O 3 particle preforms with liquid Cu or with liquid Cu8wt%Al at either 1,150 or 1,300°C, capillarity-driven transport of alumina can cause rounding of the Al 2 O 3 particles. We use quantitative metallography to show that the extent of particle rounding increases markedly with temperature and with the initial aluminum concentration in the melt. An analysis of the thermodynamics and kinetics governing the transport of alumina in contact with molten copper, considering both interfacial and volume diffusion, leads to propose two mechanisms for the rounding effect, namely (i) variations in the equilibrium concentration of oxygen in the melt as affected by the initial aluminum concentration, or (ii) segregation of aluminum to the interface with the ceramic.

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Section: Introductionmentioning

confidence: 99%

Al2O3 particle rounding in molten copper and Cu8wt%Al

Krüger

Mortensen

2012

J Mater Sci

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“…At 77 K, the GlidCop alloys are significantly stronger than the C107 used in coil 7 which has an ultimate tensile strength of 520 MPa. Since the GlidCop is strengthened by aluminum oxide precipitates, the dislocation cannot shear through the Al 2 O 3 particles [14,15]. The materials show higher strength than at room temperature because of the higher strain hardening rates at cryogenic temperatures.…”

Section: Resultsmentioning

confidence: 99%

Cryogenic properties of dispersion strengthened copper for high magnetic fields

Toplosky¹,

Han²,

Walsh³

et al. 2014

AIP Conference Proceedings

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Abstract. Cold deformed copper matrix composite conductors, developed for use in the 100 tesla multi-shot pulsed magnet at the National High Magnetic Field Laboratory (NHMFL), have been characterized. The conductors are alumina strengthened copper which is fabricated by cold drawing that introduces high dislocation densities and high internal stresses. Both alumina particles and high density of dislocations provide us with high tensile strength and fatigue endurance. The conductors also have high electrical conductivities because alumina has limited solubility in Cu and dislocations have little scattering effect on conduction electrons. Such a combination of high strength and high conductivity makes it an excellent candidate over other resistive magnet materials. Thus, characterization is carried out by tensile testing and fully reversible fatigue testing. In tensile tests, the material exceeds the design criteria parameters. In the fatigue tests, both the load and displacement were measured and used to control the amplitude of the tests to simulate the various loading conditions in the pulsed magnet which is operated at 77 K in a non-destructive mode. In order to properly simulate the pulsed magnet operation, strain-controlled tests were more suitable than load controlled tests. For the dispersion strengthened coppers, the strengthening mechanism of the aluminum oxide provided better tensile and fatigue properties over convention copper.

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“…The alumina particles are hard and thermally stable at elevated temperatures approaching the melting point of the copper matrix. Much of the research on nc metals has been focused on the HP grain size strengthening effect because grain size reduction to the nanoscale range (< 100 nm) produces very large increase in the strength [1,9,12]. However, the mechanisms operative in the nanoscale grain size regime differ from those for coarse-grained materials [13].…”

Section: Introductionmentioning

confidence: 99%

Strengthening mechanisms in the nanocrystalline Cu with Al2O3

OROLINOVA¹,

ĎURIŠIN²,

ĎURIŠINOVÁ³

et al. 2021

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Nanocrystalline (nc) Cu materials with Al2O3 dispersoid (1 and 5 vol.% Al2O3) were produced using the powder metallurgy (PM) techniques. The effect of reinforcement weight fraction, deformation temperature and annealing temperature (up to 800• C) on the strength properties and the microstructure was studied. Two strengthening mechanisms were considered at room temperature, strengthening by grain refinements and dispersion strengthening (DS). The strength properties of both nc Cu composites were strongly dependent on deformation temperature and material composition. The main contribution of nanometric Al2O3 particles to the strength of composites at elevated temperatures is probably the strong pinning effect on the grain/crystallite boundaries and preventing of recrystallization process. After annealing at 0.74Tm both composites were characterized by an excellent stability of strength characteristics.K e y w o r d s : dispersion strengthened nanocrystalline copper, strengthening mechanisms, strength properties, microstructure

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The microstructural basis for the mechanical properties and electrical resistivity of nanocrystalline Cu–Al2O3

Cited by 46 publications

References 33 publications

Al2O3 particle rounding in molten copper and Cu8wt%Al

Al2O3 particle rounding in molten copper and Cu8wt%Al

Cryogenic properties of dispersion strengthened copper for high magnetic fields

Strengthening mechanisms in the nanocrystalline Cu with Al2O3

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