Effect of Low Freque ncy Vibration on The Micro-structure Of The Aluminum Eutectic Alloy

Abstract

The effect of low frequency vibration (50cps) on solidification, structure and mechanical properties of aluminum eutectic alloys(Al-33%Cu, Al-11.7%Si )which is casted in pre-heated metallic moulds at different temperatures (200,300,400,500 and 5500C) was carried out in this investigation . The results show that low frequency vibration affect the solidification state , structure type and mechanical properties of the implemented alloys. Eutectic and intermetallic phases were coarsened by low frequency vibration ,the effect of which was found to increase by increasing the preheating temperatures of the metallic moulds .The solidification time is also reduced .Consequently coarsening of the micro-constituents the mechanical properties were lowered , although porosity, ultimate tensile stress(U.T.S) and eutectic cell size were reduced by vibration . The results show that the columnar growth was suppressed and equiaxed grain size were promoted . The fine lamellar structure of the eutectic was degenerated to a coarse irregular one .The effect of casting size on the extent of influence of vibration on structure and related aspects was also observed that ,with the increase in the size of the casting , the effect of the vibration is accentuated . As the preheating temperature of the moulds was increased, grain refinement effect due to vibration decreased and also the mechanical properties considerably decreased .