Study On Solidification Process Of Magnesium-based Bulk Amorphous Alloy

Mg-based amorphous alloy are regarded as a new family of promising materials with high specific strength and excellent corrosion resistance.It makes sense to make Mg-based amorphous alloy with strong glass forming ability(GFA)especially and continuously make bulk amorphous alloy under the condition of normal equipment and adopting commercial raw materialIn this paper,from the aspects of thermodynamic,kinetic and microstructure,the feature of structure of short-range order and long-term disordered and structure model of amorphous alloy;alloying effect,atomic interaction,scale effect,and configuration entropy is systematically discussed,and the influence of these factors on amorphous alloy form also is discussed,the way of inhibiting 1 growth and nucleation of crystal is introduced.This paper explained that the criterion of amorphous form ability.Through using vacuum intermediate frequency induction smelting furnaces,the high purity Mg65Cu25Y10 alloys was made.The effects of intermediate alloy,holding time and casting mould on the alloy composition homogenization were investigated by means of fluorescence spectrum analysis and observation metallographic.The results show that the smelting intermediate alloy has critical effect on alloy composition homogenization;the longer holding time is in favor of the alloy composition homogenization;casting mould could affect the segregation degree of alloy during solidification;and the protection gas could efficiently inhibit the burning of molten alloy,however,has no influence on the homogenization of chemical composition.The temperature field and the flow field of Mg65Cu25Y10 amorphous alloy in continuous solidification is simulation by the large-scale finite element software MARC.The influence of the casting speed,and mould temperature,cooling distance on the temperature field and the flow field is discussed.The optimum parameter is concluded.The casting speed is 0.010 m/s.the mould temperature is 1100 K.The cooling distance is 40 mm and cooling agent for water flow is 3 1/h.Under that circumstance,the cooling speed can be up to 100 K/s,amorphous bar for 10 mm in diameter can be more effective casted out.The continuous casting of amorphous alloy theoretically proved.