الفهرس 
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Abstract
The main objective of this work is to study the mechanical properties and microstructure analysis of the as cast and T6 A356 alloy reinforced with different volume fraction of nano¬Ab03 particles using stir casting technique.
A number of cast samples of A356 alloy were prepared by rheo-casting in a specially designed and built resistance fumace unit allowing for the addition of the Al203 nano-particles into the molten Al-Si alloy in the semi-solid state with mechanical stilTing. The cast specimens were heat treated (T6) by solubilizing at 540° C for 6hrs, followed by quenching and aging at 160°C for 6 hI’s. The microstructural features and the mechanical properties of the cast and T6 heat treated samples were investigated.
The results showed that the microstructure of the nanocomposite samples revealed grain refinement in aluminum matrix supported by evidence of refined dendrite ann length, and inter¬lamellar spacing for the nanocomposite containing I % weight fraction of 50 nm Al203 particles compared with base A356 alloy. It has caused a decrease in the dendrite ann length from 24.91 ±11.3 to 20.4 ± 6.5, and the inter-lamellar spacing in the eutectic silicon phase from 5.02 ± 1.61 to 3.42 ± 1.05. The heat treatment (T6) produces an effective change on the morphology of the eutectic silicon lamellae. This structure is seen to be dispersed homogeneously around the a-AI grain boundaries and inside the interdendritic regions. More details discussed using SEM and EDX analysis. The nanocomposites exhibited better mechanical properties when compared with the A356 monolithic alloy. The nanocomposite containing 2% weight fraction of Ah03 nanoparticles fabricated at 600°C, stilTing speed of 1000 rpm, and stilTed for I min, showed the maximum mechanical strength accompanied by significant increase in the ductility percentage, in the as cast and after heat treatment. The addition of AI203 nanoparticles caused slight decrease in hardness compared with the base alloy before and after T6 treatment. Porosity % increases with increasing vol. % of AI203 nanoparticles.
Keywords:
Aluminium silicon hypoeutectic alloys, Ab03 Nano-dispersions, strength, T6, grain refinement, SEM -analysis.
The main objective of this work is to study the mechanical properties and microstructure analysis of the as cast and T6 A356 alloy reinforced with different volume fraction of nano¬Ab03 particles using stir casting technique.
A number of cast samples of A356 alloy were prepared by rheo-casting in a specially designed and built resistance fumace unit allowing for the addition of the Al203 nano-particles into the molten Al-Si alloy in the semi-solid state with mechanical stilTing. The cast specimens were heat treated (T6) by solubilizing at 540° C for 6hrs, followed by quenching and aging at 160°C for 6 hI’s. The microstructural features and the mechanical properties of the cast and T6 heat treated samples were investigated.
The results showed that the microstructure of the nanocomposite samples revealed grain refinement in aluminum matrix supported by evidence of refined dendrite ann length, and inter¬lamellar spacing for the nanocomposite containing I % weight fraction of 50 nm Al203 particles compared with base A356 alloy. It has caused a decrease in the dendrite ann length from 24.91 ±11.3 to 20.4 ± 6.5, and the inter-lamellar spacing in the eutectic silicon phase from 5.02 ± 1.61 to 3.42 ± 1.05. The heat treatment (T6) produces an effective change on the morphology of the eutectic silicon lamellae. This structure is seen to be dispersed homogeneously around the a-AI grain boundaries and inside the interdendritic regions. More details discussed using SEM and EDX analysis. The nanocomposites exhibited better mechanical properties when compared with the A356 monolithic alloy. The nanocomposite containing 2% weight fraction of Ah03 nanoparticles fabricated at 600°C, stilTing speed of 1000 rpm, and stilTed for I min, showed the maximum mechanical strength accompanied by significant increase in the ductility percentage, in the as cast and after heat treatment. The addition of AI203 nanoparticles caused slight decrease in hardness compared with the base alloy before and after T6 treatment. Porosity % increases with increasing vol. % of AI203 nanoparticles.
Keywords:
Aluminium silicon hypoeutectic alloys, Ab03 Nano-dispersions, strength, T6, grain refinement, SEM -analysis.
The main objective of this work is to study the mechanical properties and microstructure analysis of the as cast and T6 A356 alloy reinforced with different volume fraction of nano¬Ab03 particles using stir casting technique.
A number of cast samples of A356 alloy were prepared by rheo-casting in a specially designed and built resistance fumace unit allowing for the addition of the Al203 nano-particles into the molten Al-Si alloy in the semi-solid state with mechanical stilTing. The cast specimens were heat treated (T6) by solubilizing at 540° C for 6hrs, followed by quenching and aging at 160°C for 6 hI’s. The microstructural features and the mechanical properties of the cast and T6 heat treated samples were investigated.
The results showed that the microstructure of the nanocomposite samples revealed grain refinement in aluminum matrix supported by evidence of refined dendrite ann length, and inter¬lamellar spacing for the nanocomposite containing I % weight fraction of 50 nm Al203 particles compared with base A356 alloy. It has caused a decrease in the dendrite ann length from 24.91 ±11.3 to 20.4 ± 6.5, and the inter-lamellar spacing in the eutectic silicon phase from 5.02 ± 1.61 to 3.42 ± 1.05. The heat treatment (T6) produces an effective change on the morphology of the eutectic silicon lamellae. This structure is seen to be dispersed homogeneously around the a-AI grain boundaries and inside the interdendritic regions. More details discussed using SEM and EDX analysis. The nanocomposites exhibited better mechanical properties when compared with the A356 monolithic alloy. The nanocomposite containing 2% weight fraction of Ah03 nanoparticles fabricated at 600°C, stilTing speed of 1000 rpm, and stilTed for I min, showed the maximum mechanical strength accompanied by significant increase in the ductility percentage, in the as cast and after heat treatment. The addition of AI203 nanoparticles caused slight decrease in hardness compared with the base alloy before and after T6 treatment. Porosity % increases with increasing vol. % of AI203 nanoparticles.
Keywords:
Aluminium silicon hypoeutectic alloys, Ab03 Nano-dispersions, strength, T6, grain refinement, SEM -analysis.