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在消失模-熔模铸造AZ91D镁合金的凝固过程中施加机械振动,研究在不同浇注温度、振幅和振动频率下消失模-熔模铸造AZ91D镁合金组织的变化。结果表明,施加机械振动后获得组织中的树枝晶明显减少,随着浇注温度的降低镁合金组织逐渐被细化,但浇注温度过低不利于机械振动发挥最佳效果,在730℃时获得组织较为理想,晶粒主要呈等轴状。随着振动频率的增大,合金组织细化,当振动频率为100Hz时细化效果最好,初生α相的晶粒尺寸仅为166.4μm,β相也基本以细小颗粒状分布。增大振幅能使镁合金晶粒尺寸明显减小,在振幅为1.0mm时获得的晶粒最为细小、圆整。
Mechanical vibration was applied during the solidification process of the lost foam - investment cast AZ91D magnesium alloy to study the microstructure evolution of the lost - investment cast AZ91D magnesium alloy at different casting temperatures, amplitudes and vibration frequencies. The results showed that the dendrites in the obtained microstructure decreased obviously after the mechanical vibration was applied. The microstructure of the magnesium alloy was gradually refined with the decrease of the pouring temperature. However, the pouring temperature was too low to be conducive to the best mechanical vibration. The microstructure of the microstructure was obtained at 730 ℃ More ideal, the grains are mainly equiaxed. With the increase of vibration frequency, the microstructure of the alloy is refined. When the vibration frequency is 100Hz, the refining effect is the best. The grain size of the primary α phase is only 166.4μm, and the β phase is basically distributed in the form of small particles. Increasing the amplitude can significantly reduce the grain size of the magnesium alloy, and the most fine and round grains obtained at an amplitude of 1.0 mm.