Study On Effect Of Mechanical Vibration On Aluminum Alloy Via Lost Foam Casting Fill And Solidification

LFC is called as technology for the21century, and is the most promising one of the casting method, because of its advantages including precision forming, clean production, and shows its great vitality and wide application prospect. But for aluminum alloy in LFC, aluminum melt is more prone to oxidize and absorb gas because pouring temperature of aluminum melt is much higher than that of the empty cavity casting process. In addition, the low coefficient of heat accumulation of sand in LFC process lowers the solidification rate and the casting tend to mushy solidification, Therefore the aluminum alloy via LFC has some disadvantages, such as large grain microstructure, bad shrinkage porosity and shrinkage void, lower mechanical properties, these disadvantages have become the major barrier which limits the application of aluminum alloy via LFC. The objective of this paper is to investigate the influence of vibration frequency as well as the amplitude on the filling and solidification processes of ADC12aluminum and ZL108aluminum alloy during its gravity die casting process. Try to find a new method of producing high-strength aluminum alloy via LFC.In this research including the fluidity of metal, shrinkage porosity, grain size and mechanical characteristic of ADC12aluminum and ZL108aluminum alloy, was investigated based on filling and solidification experiment. Conclusions could be drawn as follows:Suitable pouring temperature was700℃, in the case of vertical vibrating at amplitude of0.04mm, the fluidity of ADC12aluminum was the best when the vibration frequency increased to100HZ. In the case of vertical vibration at vibration frequency of50HZ, the fluidity of ADC12aluminum was the best when the vibration amplitude reached to0.24mm. With the vibration frequency or amplitude increasing, with led to shrinkage porosity of the sample relieving. In addition the grain was tiny and its shape become more globular because of the increase of vibration frequency and amplitude, which resulted in better strength. But the strength reduced with the increase of vibration frequency and amplitude after the maximum.The effects of vibration on the fluidity and the feeding ability of molten metal and the grain refining was studied in this paper. Studies have shown that:It was revealed that the fluidity of the metal reduced with the increase of vibration frequency and amplitude, leading to the degree of fluid turbulence and additional flow resistance increasing and holes of solidified structure emerging and the strength reduced. The mechanical vibration model of dendrite fragmentation is researched, and the research shows that the bigger the peak acceleration is, the dendrites could be broken more easily and grains refinement is better.