Influence of Al2O3 nano-dispersions on microstructure features and mechanical properties of cast and T6 heat-treated Al Si hypoeutectic Alloys

Nanoreinforced Cast Al-Si Alloys with Al2O3, TiO2 and ZrO2 Nanoparticles

“…The first step in this work was to statistically-analyze the results obtained through previous work by the authors (represented by nine samples for each condition), for A356 alumina (Al2O3) nanoreinforced cast alloys [16][17][18], on the relation between the tensile strength and the amount of nanoparticles added (in weight%) and the addition temperature. The ANOVA technique was applied on the responses to find fisher factors (f) and compare it with the tabulated values at the levels of confidence (90%, 95%, and 99%), using response surface methodology (RSM) technique.…”

“…The addition of the nanoparticles was made either at 710 °C or 640 °C in the liquid or semisolid state, respectively, by direct immersion of small packages of alumina nanoparticles wrapped in aluminum foil with simultaneous mechanical stirring of the melt. The melting and casting conditions are fully presented in previous work [16][17][18]. In the case of liquid state, the melt was brought to 700 °C when the addition was made, then stirred and poured.…”

“…Prospects of using nanoparticles as refining and reinforcement agents to gain improved performance of Al-Si cast alloys by adding Al2O3 and TiO2 particles have gained significant interest recently [16][17][18][19][20][21][22].…”

“…It has been shown that enhanced as-cast properties of Al-Si alloys are obtained by treating the melt with nano-sized particles [16][17][18][19][20][21][22]. Introducing Al2O3 nanoparticles to the (A356) cast alloy in the semi-solid state with mechanical stirring has a beneficial effect on improving the strength-ductility relationship in these alloys [16,17].…”

“…Moreover, the enhanced viscosity of the semi-solid processing would serve to improve the ceramic particle/melt wettability and entrap or capture the reinforcement material physically. The addition of ceramic particles to aluminum alloys raises the viscosity very quickly [24], providing suitable conditions for particle capture; moreover, the Al2O3 nanoparticles possess appropriate properties that are compatible with the Al alloy relatively high thermal conductivity and thermal expansion coefficients that affects its role as a nanodispersion for reinforcement in the Al alloy matrix [16][17][18][19].…”