Microstructure and thermal stability of nanostructured Cu-7.5vol.%Al2O3composite powders produced by high energy mechanical milling

Mukhtar, Aamir; Zhang, Deliang; Kong, Charlie; Munroe, Paul

doi:10.1088/1757-899x/4/1/012005

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…On account of the low price, Al 2 O 3 particles have been mostly selected as the reinforcement phase [5][6][7]. The uniform distribution of Al 2 O 3 particles can be accomplished by the process of internal oxidation [8,9] or by mechanical alloying [10,11].…”

Section: New Copper-based Alloysmentioning

confidence: 99%

Copper alloys with improved properties: standard ingot metallurgy vs. powder metallurgy

Jovanović¹,

Rajković²,

Cvijović‐Alagić³

2014

Metall Mater Eng

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Three copper-based alloys: two composites reinforced with Al 2 O 3 particles and processed through powder metallurgy (P/M) route, i.e. by internal oxidation (Cu-2.5Al composite) and by mechanical alloying (Cu-4.7Al ) and Cu-0.4Cr-0.08Zr alloy produced by ingot metallurgy (vacuum melting and casting) were the object of this investigation. Light microscope and scanning electron microscope (SEM) equipped with electron X-ray spectrometer (EDS) were used for microstructural characterization. Microhardness and electrical conductivity were also measured. Compared to composite materials, Cu-0.4Cr-0.08Zr alloy possesses highest electrical conductivity in the range from 20 to 800 o C, whereas the lowest conductivity shows composite Cu-2.5Al processed by internal oxidation. In spite to somewhat lower electrical conductivity (probably due to inadequate density), Cu-2.5Al composite exhibits thermal stability enabling its application at much higher temperatures than materials processed by mechanical alloying or by vacuum melting and casting.

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Section: New Copper-based Alloysmentioning

confidence: 99%

Copper alloys with improved properties: standard ingot metallurgy vs. powder metallurgy

Jovanović¹,

Rajković²,

Cvijović‐Alagić³

2014

Metall Mater Eng

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“…The second 12 hours milling using larger balls in Route 2 caused significant refinement of the grains into the size range of 50-150nm, as shown in Figure 8(e). Nanostructured Cu-7.5vol.%Al 2 O 3 and Cu-10vol.%Al 2 O 3 composite powders were produced by Mukhtar et al [88] from a mixture of Cu powder and Al 2 O 3 nanopowder using two routes of high energy mechanical milling. The as-milled and annealed nanocomposite powder particles showed little increase of the Cu matrix grain sizes and decrease of micro-hardness after annealing at temperatures up to 400℃.…”

Section: Cu-based Nanomaterials and Nanocompositesmentioning

confidence: 99%

Mechanical Milling: a Top Down Approach for the Synthesis of Nanomaterials and Nanocomposites

Yadav¹,

Yadav²,

Singh³

2012

532

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Synthesis of nanomaterials by a simple, low cost and in high yield has been a great challenge since the very early development of nanoscience. Various bottom and top down approaches have been developed so far, for the commercial production of nanomaterials. Among all top down approaches, high energy ball milling, has been widely exploited for the synthesis of various nanomaterials, nanograins, nanoalloy, nanocomposites and nano -quasicrystalline materials. Mechanical alloying techniques have been utilized to produce amorphous and nanocrystalline alloys as well as metal/non-metal nanocomposite materials by milling and post annealing, of elemental or compound powders in an inert atmosphere. Mechanical alloying is a non-equilibrium processing technique in which different elemental powders are milled in an inert atmosphere to create one mixed powder with the same composition as the constituents. In high-energy ball milling, plastic deformation, cold-welding and fracture are predominant factors, in which the deformation leads to a change in particle shape, cold-welding leads to an increase in particle size and fracture leads to decrease in particle size resulting in the formation of fine dispersed alloying particles in the grain-refined soft matrix. By utilizing mechanical milling various kind of aluminium/ nickel/ magnesium/ copper based nanoalloys, wear resistant spray coatings, oxide and carbide strengthened aluminium alloys, and many other nanocomposites have been synthesized in very high yield. The mechanical milling has been utilized for the synthesis of nanomaterials either by milling and post annealing or by mechanical activation and then applying some other process on these activated materials. This review is a systematic view of the basic concept of mechanical milling, historical view and applications of mechanical milling in the synthesis of various nanomaterials, nanosomposites, nnaocarbons and nano quasicrystalline materials.

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“…between 880 and 950°C [3][4][5][6][7][8] . Applying high-energy millling of a mixture of Cu and Al 2 O 3 powders a considerably high microhardness (250 HV) has recently been obtained [9] , but with a relatively low thermal stability. After exposure at 500°C for 1h the microhardness of this material decreased sharply to 183 HV.…”

Section: Introductionmentioning

confidence: 99%

Strength and thermal stability of Cu-Al2O3 composite obtained by internal oxidation

Rajković¹,

Božić²,

Devečerski³

et al. 2010

REVMETAL

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The objective of the work is to study the effects of the high-energy milling on strengthening, thermal stability and electrical conductivity of Cu-Al 2 O 3 composite. The prealloyed copper powders, atomized in inert gas and containing 3 wt. % Al, were milled up to 20 h in the planetary ball mill to oxidize in situ aluminium with oxygen from the air. Composite compacts were obtained by hot-pressing in an argon atmosphere at 800°C for 3 h under the pressure of 35 MPa. The microstructural characterization was performed by the optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction analysis (XRD). The microhardness, electrical conductivity and density measurements were also carried out. The effect of internal oxidation and high-energy milling on strengthening of Cu-Al 2 O 3 composite was significant, The increase of the microhardness of composite compacts (292 HV) is almost threefold comparing to compacts processed from the as-received Cu-3 wt. % Al powder (102 HV). The grain size of Cu-Al 2 O 3 compacts processed from 5 and 20 h-milled powders was 75 and 45 nm, respectively. The small increase in the grain size and the small microhardness drop indicate the high thermal stability of Cu-Al 2 O 3 composite during high-temperature exposure at 800°C. KeywordsPowder processing; Metal matrix composites; Microstructural characterization; Microhardness; High-temperature properties. Resistencia y estabilidad térmica del compuesto Cu-Al 2 O 3 obtenido con oxidación interna ResumenEl objetivo del trabajo es el estudio de los efectos de la pulverización con altas energías sobre la resistencia, estabilidad térmica y conductividad eléctrica del compuesto Cu-Al 2 O 3 . El polvo pre-aleado de cobre, obtenido a través de la atomización con gas inerte y con un contenido de 3wt. % Al, se molió durante 20 h en el molino planetario de bolas dando lugar a la oxidación in situ del aluminio con el oxígeno del aire. El compuesto compactado se ha obtenido mediante prensado en caliente en atmósfera de argón a 800°C durante 3 h y a una presión de 35 MPa. La caracterización microestructural se hizo a través de microscopia óptica, microscopia electrónica de barrido (SEM), microscopia electrónica de transmisión (TEM) y difracción de rayos X (XRD). También se realizaron medidas de micro-dureza, de conductividad eléctrica y de densidad. La micro-dureza de los compuestos compactados (102 HV) aumentó casi tres veces comparada con la de los obtenidos del polvo Cu-3 wt. % Al (102 HV). El tamaño de grano del compactado Cu-3 wt. % Al fue 75 y 45 nm después de 5 y 20 h de pulverización, respectivamente. El pequeño aumento del tamaño de grano y la pequeña caída de micro-dureza del compuesto Al 2 O 3 indican alta estabilidad térmica durante la exposición a altas temperaturas de 800°C. Palabras clavesProcesado de polvo; Compuestos metal-matriz; Caracterización microestructural; Microdureza; Propiedades a altas temperaturas.

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Microstructure and thermal stability of nanostructured Cu-7.5vol.%Al₂O₃composite powders produced by high energy mechanical milling

Cited by 4 publications

References 9 publications

Copper alloys with improved properties: standard ingot metallurgy vs. powder metallurgy

Copper alloys with improved properties: standard ingot metallurgy vs. powder metallurgy

Mechanical Milling: a Top Down Approach for the Synthesis of Nanomaterials and Nanocomposites

Strength and thermal stability of Cu-Al<sub>2</sub>O<sub>3</sub> composite obtained by internal oxidation

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