Mechanical properties of seramic particulate reinforced Al-Si based metal matrix composite materials fabricated by squeeze casting

ABSTRACT Advanced technology causes new applications to be developed in the materials science. It is also noticed that technological structure of materials became available from alloying point. Composites are widely used in automotive, aerospace, naval and medical industries. Development in the aerospace and automotive industries have influenced and forced traditional materials performance. For this reason, it can be said that composites are the materials of the future. To overcome problems in the different advanced technological applications and restrictions in the production cost are the main aims of researches. Therefore important parameters in composites are to select and improve proper casting method, and forming possibility. Al Si7 Mg2 aluminum alloy has been employed as a metal matrix, between the dimensions of 30-60 ym particulate silicon carbide (SiC) were used as reinforcement with % wt 5,10,15. AMCs have been fabricated by gravity and squeeze casting processes. After squeeze casting some composites are heated up to 400 °C and kept for one hour at this temperature and then these samples have been forged. Different production methods and various reinforcement rates were investigated from density, hardness, tensile stress, impact strength (charpy) and microstructures points. Composites produced by squeeze casting method showed significant increase in tensile stress and hardness. Compare to gravity casting, grain size in composites under pressure and high cooling rate were small. The main factor to develop the mechanical properties of this casting method is to increase strength between reinforcement are matrix bond. Especially macrospace after gravity casting almost decreased after squeeze casting. Also possible porosity between interface-reinforcement and interface-matrix can be prevented by squeeze casting method. It has been observed that hard brittle intermetallic structure percentage decreased at squeeze casting. Key Words: Composite, squeeze casting, metal matrix, silicon carbide, particle. Xll