Developing Cost-effective Lightweight Cast-Nanocomposites

Project: Research project

Grant Program

ORAU Grant

Project Description

In the proposed project, high-performance, ultralight, nanoparticulate-reinforced aluminum- and magnesium-matrix composites will be developed using low-cost metal casting processes which can be productionized in the Kazakhstani foundries, enhancing their competitiveness. The composites will be produced using low cost nanoparticles obtained from fly ash, the abundant solid inorganic by-product of coal-fired power production.
Solidification techniques, primarily stir-mixing, will be suitably modified and extended to synthesize aluminum- and magnesium-matrix nanocomposites. Special high shear mixing and ultrasonic energy dispersion processes will facilitate the de-agglomeration and mixing of nano-sized ash particles into molten Al and Mg alloys, i.e. A356, A206, AZ91D and ZC63 and assure their uniform dispersion in ultra-high performance aluminum and magnesium castings. Modeling and theoretical analysis work will be done both prior to- and concurrently with the experimental work, to identify optimum processing conditions. A comparison of the modeling and theoretical analysis results with those of laboratory-scale experiments on synthesis and casting of nanostructured Al- and Mg-composites will be used to refine the models. Cast microstructures will be characterized and selected properties will be measured to identify the optimum processes and compositions based on the relationships between processing, structure, and properties. Selected components made from nanoparticle-reinforced aluminum and magnesium alloys will be designed and cast whereas mechanical testing will evaluate the performance of components made in the proposed project. Final alloy composition and processing will be optimized to obtain targeted component properties, i.e. ultimate tensile strength to the point of 600 MPa, outstanding fatigue limit to the point of 150 MPa and performance, i.e. improved tribological properties: friction coefficient lower than 0.25 and wear rate between 10-12 and 10-13 m3/N·m.

Key findings

The key project result is the confirmation of hypotheses H1 and H2: The reduction of CFA particle size by high-energy milling will increase strength and lessen the penalty to ductility and toughness of CFA-Al composites. Mixing by means of a reciprocating grid will improve the dispersion and deagglomeration of CFA in a CFA-Al composite, compared to stir-casting.
The project also evidenced a large variability of CFA composition between different sources, which makes it an impractical material to work with, as a number of constituents in CFA, particularly Ca and Fe oxides, have poor compatibility to the Al matrix and may be detrimental. Overall, it was concluded that ultra-fine CFA-Al composites produced by reciprocating grid mixing and casting carry some benefits over stir-cast CFA-Al, but are inferior to commercially available composites of a more controlled composition, such as SiC-Al, leaving support for hypothesis H3.
At the same time, the project has served to kick-off nanocomposites research at Nazarbayev University. A number of new projects with more promising materials have been incubated in the research team and industrial partners have been attracted.
Short titleNANO-CAST
StatusFinished
Effective start/end date1/1/1612/31/18

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Nanocomposites
Ashes
Magnesium
Composite materials
Magnesium castings
Processing
Metal casting
Nanoparticles
Aluminum castings
Aluminum
Costs
Mechanical testing
Foundries
Magnesium alloys
Chemical analysis
Fly ash
Byproducts
Solidification
Molten materials
Aluminum alloys