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为了深入了解定向凝固过程生长速率对杆形Mn Bi合金共晶间距的影响,开展了试验和数值模拟研究工作,以期初步明确在地球上试验得到的杆形共晶间距和在外层空间(航天飞机上)同样试验条件下得到的杆形共晶间距发生变化这样一个事实的机理。在杆形MnBi共晶相和Bi基体生长前沿,用传质方程计算了Mn在合金液中的浓度场,得到了液、固两相间台式界面前沿Mn的等浓度曲线,进而依据Jackson Hunt研究的理论模型计算出杆形共晶间距。试验和数值模拟的结果显示,规则生长时,随着Peclet数Λ的不断增加,杆形共晶间距逐渐减少,试验与模拟的结果吻合良好。Λ数还可在将来被用来模拟计算该合金凝固时非规则生长时的情况。
In order to understand the effect of the growth rate of directional solidification process on the eutectic spacing of rod-shaped Mn-Bi alloy, experiments and numerical simulations were carried out in order to clarify the pole-shaped eutectic spacing and the outer space On) the same test conditions obtained rod-shaped eutectic spacing of such a fact that the mechanism. The concentration field of Mn in the alloy liquid was calculated by the mass transfer equation at the front of rod-shaped MnBi eutectic and Bi matrix growth, and the isoconcentration curve of front Mn of liquid-solid two-phase interface was obtained. According to Jackson Hunt The theoretical model calculates the rod-shaped eutectic spacing. The experimental and numerical simulation results show that the rod-shaped eutectic spacing decreases gradually with the increase of Peclet number Λ, and the results agree well with the experimental results. The number of A can also be used in the future to simulate the situation when the alloy solidifies irregularly.