材料期刊网

研究了波浪型倾斜板振动参数对Al--6Si--2Mg合金凝固组织的影响, 结果表明:倾斜板的倾角和长度影响合金在斜板表面的流动剪切强度和剪切时间, 从而影响合金的组织.当浇注温度为660 --690℃时, 随着浇注温度的降低, 合金晶粒细化和球化,平均晶粒直径为40μm, 晶粒平均圆度值为2.5; 浇注温度低于660℃时,晶粒有粗化和枝晶化的趋势. 倾斜板的振动作用使表面形成的晶核离开表面进入熔体中,有效地减少了晶粒之间的粘连, 解决了结壳问题, 提高了形核率,  细化了组织;随着倾斜板振动频率的提高, 晶粒的平均圆度先降低后提高, 振动频率为50--60 Hz 出现最小值.倾斜板的波浪形表面对流动的金属具有搅拌作用, 增大了熔体内部的剪切作用,使晶粒更加细小圆整.

Effects of parameters of Vibrating Wavelike Sloping Plate process (VWSP) on solidification microstructures  of Al–6Si–2Mg alloy were investigated. The results show that sloping angle and sloping plate length can  affect the shear strength and shear time of the flow alloy on the sloping plate and thus influence alloy  microstructure. When the casting temperature is in the range from 660℃ to 690 ℃, grain refining and  spheroidization proceed with the decrease of casting temperature, the average grain size is 40 μm and  the average grain roundness is 2.5. When the casting temperature is lower than 660℃, dendrite  coarsening appears. The vibrating of the sloping plate can lead the nucleus forming on the sloping plate  surface to escape off the sloping plate and disperse in the melt, which not only can effectively avoid grain  connecting and solidification shell happening but also can improve the nucleation rate and refine microstructure.  With the increase of vibration frequency, grain roundness decreases first and then increases, when the vibration  frequency is in the range from 50 Hz to 60 Hz, the grain roundness reaches the minimum value. Wavelike sloping  plate surface had a stirring function on the flowing alloy, which improved the shear strength in the alloy and  caused grains became finer and more round.