摘要
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。
Numerical and experiment work is carried out to investigate the effect of growth rate during directional solidification process on the rod spacing of MnBi eutectic alloy, which is the first step to understand the mechanism of the rod spacing change at experiment in outer space as compared to that on earth. The concentration fields in the front of the MnBi eutectic and Bi matrix have been computed by using mass transfer equation, the obtained average concentration of melt at a stepped interface between liquid and solid phases is then used to calculate the rod spacing based on the theoretical model developed by Jackson and Hunt. The simulated results agree well with experiment.The rod spacing decreases as the Peclet numberΛincreases for regular growth,which may be used to model the irregular growth for the eutectic alloy in a new task in the near future.
出处
《铸造》
CAS
CSCD
北大核心
2003年第6期395-399,共5页
Foundry
