According to articles I've added 5 percent alumina to molten (aluminum) but the amount of dissolution were low and it were exposed a lot of powders on the surface of the molten.
I can't understand, can anyone help me?
"The Al2O3 nano-particles were heated at 400˚C for two hours before dispersion inside the vortex formed due to stirring." - check attachment
It should be noted that melting temperature of Al alloys is approximately 650 C but melting temperature of Al2O3 is 2072 C. I think that you want to mean homogeneous distribution or yield. For homogeneous distribution of Al2O3 particles within Al356 alloy matrix, you can used stir casting method with optimized parameters (temperature, stirr speed, preheating temperature of Al2O3 particles, coating of Al2O3 particles...). Moreover, you have to remember that wettability of Al2O3 particles by Al matrix is bad and so you should be added Magnesium into the melting.
For more information, you shoul examined attaced paper.
@Temel
Thanks for attached publication!
A356 is Al and Si (~6%) alloy (good casting characteristics + corrosion-resistant), AA2024 contains 4.4% copper, 1.5% magnesium, 0.6% manganese and 93.5% aluminium by weight - it is high strength alloy with low corrosion resistance.
@All
Magnesium addition is good, but it will produce another alloy. Infact, all metals have good wetting properties to their oxides, and aluminium is not exclusion. At extremely low oxygen pressure wetting angle is low as 90°. But traces of O2 (>3.8 × E-11 bar) build on surface very thin film of oxide. Role of magnesium in wetting promotion is possible on covering of Al2O3 with thin MgO film. This idea supported experementally. Coating of Al2O3 with some MgO lead to wettable powder. Segregation of AI2O3 particles along the grain boundaries and some coagulation of Al2O3 within the grain can be detected .
Based on this observation, could be speculate, that Al2O3 particles, precoated with termally unstable Mg salts, after calcination will possess with good wettability, by constant alloy composition. Such approach may be usefull by application to mineral nanofibers.
Mg addition would reduce the surface tension in the liquid melt which will assist easy wetting over the Al203 surface provided the reinforcement surface tension is high. This would be possible by preheating the ceramic particle above 1000Deg C. If you properly control the flow rate of Al203 particle into the melt over the period, then the stirring would assist uniform distribution
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