抽拉速率对镍基单晶高温合金组织和偏析的影响（英文）

Effects of Elevated Withdrawal Rate on the Microstructure and Segregation Behavior of a Nickel-base Single Crystal Superalloy

研究了抽拉速率对一种镍基单晶高温合金组织和成分偏析的影响。结果表明:随着抽拉速率的提高,一次枝晶间距与二次枝晶间距缩小,γ'相尺寸减小;γ/γ'共晶随着抽拉速率的提高,尺寸变小,但体积分数增加;同时,随着抽拉速率的提高,单晶成分偏析增加。

The effects of withdrawal rate on the microstructure and segregation behavior of a nickel-base single crystal superalloy were investigated. The results indicate that by increasing the withdrawal rate, the primary dendrite ann spacing （λ1）, the secondary dendrite arm spacing （λ2） and the size of γ＇ precipitates decrease gradually. Moreover, the shape of γ＇ precipitates is more regular at higher withdraw rates. Also, the size of γ/γ＇ eutectic becomes small while the total volume fraction increases. Considering the composition segregation is determined by diffusion time of the constituent elements, when withdrawal rate is elevated, diffusion time of solutes decreases, and the effects of segregation are enhanced.