scholarly journals Microstructure And Mechanical Properties of Ultrasonically Processed Al-7Si Alloy / Y2O3 Nanocomposite

Author(s):  
T. Satish Kumar ◽  
Jayakrishnan Nampoothiri ◽  
S. Shalini

Abstract The aim of the present study is to investigate the microstructure and mechanical properties of the A356 aluminum metal matrix composite reinforced with Y2O3 particles. The composite is synthesized by adding 1 and 2 vol.% of reinforcement via stir casting assisted by ultrasonic treatment (UT). Microstructural contemplates shows improvement in the dispersion of nano Y2O3 particles and decrease in the porosity level due to the ultrasound aided synthesis. The UT refines the size of the Y2O3 particles as well as helps to improve its dispersion. The secondary dendrite arm spacing of 2 vol.% Y2O3 reinforced samples with 5 min UT is found to be significantly reduced to 12 µm as compared to that of the as-cast A356 alloy. Addition of 2 vol.% of nano Y2O3 has significantly improved the hardness of the A356 alloy from 60 HV to 108 HV. A considerable increment in the YS and TS of the A356 alloy is observed with the of Y2O3 and found to further improve with UT. However, small reduction in ductility is observed with the addition of Y2O3 as well as ultrasonic treatment.

Author(s):  
Amneesh Singla ◽  
Rajnish Garg ◽  
Mukesh Saxena

A 356 alloy reinforced with insitu V2O5 particles by using stir casting technique. The composites were produced by the addition of oxide particles in different weight percentage. The effect of oxide powder addition on microstructure and mechanical properties of produced composites were investigated. The effect of heat treatment on microstructure and mechanical properties were investigated by optical microscope, Microhardness tester and tension test. A significant improvement in hardness and tensile strength was revealed in the produced composite as compared to the base alloy. With the addition of oxide particles, the shape and size of eutectic Si changed which in turn affects the properties. It was observed that 2h solutionizing followed by the artificial aging was sufficient to make the structure homogenize and to produce the hardening precipitates. The improvement in the mechanical properties has been observed due to the age hardening precipitates in addition with refinement of insitu V2O5 particles.


2013 ◽  
Vol 750-752 ◽  
pp. 687-690 ◽  
Author(s):  
Su Zhang ◽  
Gang Yang ◽  
Jian Hong Yi ◽  
Hong Yan

Effects of the holding time and the stirring time on the microstructure and mechanical properties of A356 alloy modified by Sc are researched. According to the test results, most of the eutectic silicon phases have changed to the shape of creeping point, dispersed in the grain boundary of α (Al) phase while stirring 1 minute, in which case both the tensile strength and elongation reach the highest, resulting in the best modification effect. The results also indicate that microstructure and mechanical properties of the alloy reach are the best modification effect when the melt is held 15 minute. It can be known that the optimal stirring time is 1 minute and the optimal holding time is 15 minute in the experiment condition of the work.


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