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在1g的重力加速度条件下,研究熔体对流对向上生长的定向凝固Pb-33%Sn合金枝晶生长行为的影响。熔体对流由行波磁场进行调制。当行波磁场方向由向上转变为向下时,一次枝晶间距逐渐增大,一次枝晶间距的分布更加紧凑,且峰值趋于降低。分析表明:行波磁场对熔体对流的调制作用与改变重力加速度的效果类似,当抽拉速率为50μm/s,行波磁场强度为1mT时,在向上和向下的行波磁场作用下有效重力加速度分别为3.07g和0.22g。
The effects of melt convection on the directional growth of directional solidification Pb-33% Sn dendrite were investigated at 1 g of gravitational acceleration. Melt convection is modulated by a traveling-wave magnetic field. When the direction of the traveling wave magnetic field changes from upward to downward, the primary dendrite spacing increases gradually, the distribution of primary dendrite spacing becomes more compact and the peak value tends to decrease. The analysis shows that the modulation effect of traveling magnetic field on melt convection is similar to that of gravity acceleration. When the pullout rate is 50μm / s and the traveling wave magnetic field strength is 1mT, it is effective under the upward and downward traveling magnetic field The gravitational accelerations were 3.07 g and 0.22 g, respectively.