Thermal stability of nanostructured aluminum powder synthesized by high-energy milling

Abdoli, Hamid; Ghanbari, M.; Baghshahi, Saeid

doi:10.1016/j.msea.2011.05.057

Cited by 31 publications

(20 citation statements)

References 43 publications

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“…DSC curves of Al6063 show a single endothermic event at 675 and 663°C for GA and MM powders, respectively, related to the melting of alloys. A similar shift in the position of DSC peak after mechanical milling has been previously reported by Abdoli et al [34]. It is well established that the melting temperature of nanostructured solids decreases with decreasing their crystal size [35].…”

Section: Powder Characteristicssupporting

confidence: 86%

Sintering Behavior of Nanocrystalline Al6063 Powders Prepared by High-Energy Mechanical Milling

Asgharzadeh

2016

Trans Indian Inst Met

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Nanocrystalline Al6063 powders were synthesized by high-energy mechanical milling of gas-atomized powders for 22.5 h. The powders were uniaxially compacted at various compaction pressures ranging 200-1325 MPa and then were sintered at temperatures between 550 and 650°C for 1 h. The densification and microstructural evolutions during both solid phase sintering and supersolidus liquid phase sintering are studied. Ultrafine-grained (UFG) Al alloy compacts show superior sinterability compared with coarsegrained (CG) compacts due to the higher defect density and larger specific surface area of the mechanically-milled powders. The densification parameter and hardness of both CG and UFG Al6063 compacts enhances as the compaction pressure increases. Nevertheless, applying high compaction pressures has an adverse effect on the sintered density and results in the swelling of compacts. The results point out an optimum sintering temperature at *600°C for achieving the highest sintered density and hardness with minimal grain coarsening and slumping.

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Section: Powder Characteristicssupporting

confidence: 86%

Sintering Behavior of Nanocrystalline Al6063 Powders Prepared by High-Energy Mechanical Milling

Asgharzadeh

2016

Trans Indian Inst Met

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“…There are reports of modifications to grain size in Al particles that result from annealing and quenching [21,22]. However, visualizing the grains, grain boundaries, and grain distributions within an individual Al particle has not previously been reported.…”

Section: Focused Ion Beam (Fib) Cross-sectioning and Tem Lattice Imagingmentioning

confidence: 99%

“…The average strain for µAl annealed to 300 °C increased by 660% [20]! Others also studied annealing and quenching μAl particles in order to observe changes in mechanical properties [21,22]. Bachmaier and Pippan [21] and Abdoli et al [22] found that when consolidating pre-stressed powder into a bulk material, changes occurring on the particle level affected the mechanical properties of the final bulk material.…”

Section: Introductionmentioning

confidence: 99%

“…Others also studied annealing and quenching μAl particles in order to observe changes in mechanical properties [21,22]. Bachmaier and Pippan [21] and Abdoli et al [22] found that when consolidating pre-stressed powder into a bulk material, changes occurring on the particle level affected the mechanical properties of the final bulk material. The onset for mechanical change for both studies was similar and occurred above 200 °C; and may be due to the high purity of the aluminum particles used [ 20,21].…”

Section: Introductionmentioning

confidence: 99%

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A slice of an aluminum particle: Examining grains, strain and reactivity

McCollum

Smith

Hill

et al. 2016

Combustion and Flame

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Micron-scale aluminum (Al) particles are plagued by incomplete combustion that inhibits their reactivity. One approach to improving reactivity is to anneal Al particles to increase dilatational (volumetric) strain which has also been linked to increased combustion performance. While optimal annealing temperatures have been identified (roughly 300 °C), little is known about cooling rate effects on particle combustion performance. This study examines the effect of quenching after annealing Al microparticles to 100, 200 and 300 o C on intra-particle dilatational strain and reactivity. Synchrotron X-ray diffraction analysis of the particles reveals the cooling rates in the range from 0.007 to 0.38 K/s have little effect on the dilatational strain of the aluminum-core, alumina-shell particles. The annealed and quenched Al particles were then combined with a metal oxidizer (copper oxide) to examine reactivity. Flame propagation experiments follow the same trend: flame speeds are unchanged until a critical annealing temperature of 300 °C is reached and performance is maintained for each annealing temperature regardless of cooling rate. These results show that altering the mechanical properties and combustion performance of Al particles is strongly dependent on the annealing temperature and unchanged with variation in cooling rate. The contributions from elastic and plastic deformation mechanisms on strain are also considered and additional experimental results are shown on the microstructure of an Al particle. Focused ion beam milling of an Al particle to electron transparency was combined with transmission electron microscope imaging in order to examine the microstructure of the Al particles. This confirmed that the Al microparticles have a polycrystalline structure shown by grains all exceeding 100 nm in size.

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“…Various techniques are used to prepare NAP and these are divided into high temperature and low temperature processes. The high temperature techniques include gas evaporation [13][14][15][16], plasma chemical synthesis [17][18][19][20][21][22], laser ablation [23], arc discharge [24][25][26], electro-explosion [27][28][29][30], and ion implantation [31], whereas the low temperature techniques include solution methods [32][33][34][35][36][37][38] and mechanical attrition (ball milling) [39][40]. However, producing bulk NAP continues to be a technical challenge.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Nano Aluminium Powder (NAP) using a Thermal Plasma: Process Development and Characterization

Pant¹,

Seth²,

Raut³

et al. 2016

Cent. Eur. J. Energ. Mater.

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A bottom up approach for the preparation of Nano Aluminium Powder (NAP) using a Transferred Arc Thermal Plasma Reactor (TAPR) is described. The aluminium block is subjected to evaporation by the application of a thermal plasma. The aluminium vapour produced is rapidly quenched to room temperature resulting in crystallization of the aluminium vapour in nano-particulate form. Various process parameters, such as the plasma torch power, reactor pressure and plasma gas composition were optimized. This paper also describes the characterization of NAP by analytical methods, for the estimation of the Active Aluminium Content (AAC), Total Aluminium Content (TAC), XRD, bulk density, BET surface area, HR-TEM etc. The results are compared with those for samples prepared in other thermal plasma reactors, such as the DC Arc Plasma Reactor (DCAPR) and the RF Induction Thermal Plasma Reactor (RFITPR), and for commercially available NAP samples (ALEX, prepared by the EEW technique).

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Thermal stability of nanostructured aluminum powder synthesized by high-energy milling

Cited by 31 publications

References 43 publications

Sintering Behavior of Nanocrystalline Al6063 Powders Prepared by High-Energy Mechanical Milling

Sintering Behavior of Nanocrystalline Al6063 Powders Prepared by High-Energy Mechanical Milling

A slice of an aluminum particle: Examining grains, strain and reactivity

Preparation of Nano Aluminium Powder (NAP) using a Thermal Plasma: Process Development and Characterization

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