Of late, nanotechnology seems to be rapidly thrusting its applications in all aspects of life including engineering and medicine. Materials science and engineering has experienced a tremendous growth in the field of nanocomposite development with enhanced chemical, mechanical, and physical properties. A wide array of research has been conducted in the processing of nanocomposites. Consolidation of these systems from loose particles to bulk free form entities has always been a challenge. To name a few, traditional consolidation techniques such as cold pressing and sintering at high temperatures, hot pressing, and hot isostatic pressing have strong limitations of not being able to retain the nanoscale grain size due to the excessive grain growth during processing. This article reviews in detail the results from numerous studies on various methods for manufacturing nanocomposites with improved properties and retained nanostructures. Both challenges and recent advances are discussed in detail in this review.

Challenges and advances in nanocomposite processing techniques

Nanoquasicrystalline Al–Fe–Cr-based alloys. Part II. Mechanical properties

Grain growth and kinetics for nanocrystalline magnesium alloy produced by mechanical alloying

The influence of trace Ti on the microstructure and precipitation process of a Zr-containing Al–Zn–Mg–Cu alloy was investigated The introduction of Ti results in not only the refinement of α-Al grains, but also an early-stage age hardening behavior during aging treatment process High-resolution transmission electron microscopy results indicate that Ti can decrease the coarsening tendency of L1 2 precipitates and accelerate the growth rate of GP II as well as its evolution to η' phase The mechanism was discussed Accordingly, the tensile strength, elongation and wear property were obviously improved

Influence of trace Ti on the microstructure, age hardening behavior and mechanical properties of an Al–Zn–Mg–Cu–Zr alloy

This review outlines, in great detail, the history of the phenomenon of ultrasonic nebulization of liquids since the discovery of such an effect by Michael Faraday and the explanation of the phenomenon by capillary wave mechanism and “cavitation” hypothesis. Capillary waves described by the Kelvin equation are confirmed by Lang's experiment and more theoretical models by Peskin & Raco and Jokanovic. Cavitation bubbles have been elaborated by the Rayleigh-Plesset equation as well as the correlation equations between predicted and experimentally measured droplet diameter. Correlation equations such as one by Rajan & Pandit and Avvaru et al. have been considered. Ultrasonic spray pyrolysis for materials processing and the theories that predict the final particle size distribution are introduced. The popularity of the technique is shown by the rising number of research groups in the world processing various materials by this method due to its cost-effectiveness, purity of its products, and controllability of ...

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Progress in Ultrasonic Spray Pyrolysis for Condensed Matter Sciences Developed From Ultrasonic Nebulization Theories Since Michael Faraday

Dispersion-strengthened AlTi alloys were prepared by the mechanical alloying (MA) process and hot consolidation method, and their high temperature mechanical properties and oxidation properties were investigated. The tensile strengths of MA AlTi alloys were substantially higher than those of conventional Al alloys such as 7075 and 2024 grades at temperatures above 150°C. The compressive strength and the yield strength of MA Al8wt.%Ti at 350°C with a strain rate of 1 × 10 −4 s −1 were 233 MPa and 186 MPa respectively. The measured parabolic rate constant k p in oxidation of the MA Al8wt.%Ti alloy at 600°C was a much lower value, approximately 1.12 × 10 −13 g 2 cm −4 s −1 , which revealed that the oxidation resistance of the MA alloy was much better than that of the 2024-TB Al alloy.

High temperature performance of dispersion-strengthened AlTi alloys prepared by mechanical alloying

High temperature deformation behaviour of mechanically alloyed Al-Ti alloys

The oxygen permeation flux of a La 0.7 Sr 0.3 Ga 0.6 Fe 0.4 O 3− δ (LSGF) membrane was found to be lower than commercial membranes, so nano porous La 0.6 Sr 0.4 CoO 3− δ (LSC) particles were coated on it to improve the oxygen permeation flux. The nano-porous LSC particles were synthesized with an increased surface area through the addition of a polymer on ultrasonic spray pyrolysis. The synthesized LSC particles consisted of nano-sized particles (20 nm) and the pore-size of the particles (20–100 nm) was dependent on the concentration of the added polymer. It was found that the LSGF membrane coated by the nano porous LSC particles resulted in a significant improvement in oxygen permeability.

Synthesis and optimization of nano-porous La0.6Sr0.4CoO3−δ on the oxygen separation membrane

The thermal stability of the MA Al-Ti alloy was improved by the addition V or Zr. Such improvement is attributed to the retarded coarsening of the dispersoid phases due to the improved coherency between dispersoid phases and the Al-matrix in the presence of alloying elements V and Zr. The compressive yield strength of ternary MA Al-8Ti-2.8V and Al-8Ti-5.1Zr alloys were superior to binary MA Al-STi alloy at the temperature of above 400 °C, but the MA Al-8Ti-5.1Zr alloy showed some brittleness at 450 °C.

Effect of V or Zr addition on the mechanical properties of the mechanically alloyed Al-8wt% Ti alloys

Recently, Lee and researchers at Northwestern University did extensive work on Al[sub 3](M) dispersoids with a view of understanding their coarsening resistance. In particular, fcc L1[sub 2] and DO[sub 23]-structured Al[sub 3](M) phases showed slow coarsening kinetics, and thus L1[sub 2] and DO[sub 23] phases are believed to match the matrix better than the D0[sub 22] phase. However, most of the alloy compositions adopted in these works were confined within the range of the extents of solubility limits in binary aluminum alloys, from the viewpoint of rapid solidification processing. Therefore, in the present study, the authors investigated whether Al[sub 3]Ti dispersoids could be transformed to more stable phases by the addition of vanadium or zirconium as a third alloying element to Al-8wt.%Ti alloys, through the mechanical alloying process.

Kwang-Min Lee

Papers

High temperature performance of dispersion-strengthened AlTi alloys prepared by mechanical alloying

High temperature deformation behaviour of mechanically alloyed Al-Ti alloys

Synthesis and optimization of nano-porous La0.6Sr0.4CoO3−δ on the oxygen separation membrane

Effect of V or Zr addition on the mechanical properties of the mechanically alloyed Al-8wt% Ti alloys

Effects of V and Zr addition on lattice parameters of Al3Ti phase in mechanically alloyed Al-8wt.%Ti alloys