镍基单晶高温合金对接平台内缩松缺陷的形成机制研究  

Formation Mechanism of Porosity Defects in Rejoined Platforms of Ni-based Single Crystal Superalloy

作　　者：霍苗 简航岳 陈楚玥 赵惠 HUO Miao;JIAN Hang-yue;CHEN Chu-yue;ZHAO Hui(School of Materials Science an Engineering,Xi'an Shiyou University,Xi'an 710065,China)

机构地区：[1]西安石油大学材料科学与工程学院,西安710065

出　　处：《精密成形工程》2023年第9期152-158,共7页Journal of Netshape Forming Engineering

基　　金：国家自然科学基金(5210011310);陕西省自然科学基础研究计划(2021JQ-604,2021JM-403);陕西省教育厅科研计划(21JC027)。

摘　　要：目的研究镍基单晶高温合金对接平台内的枝晶生长行为及凝固缺陷的形成机制。方法在不同抽拉速率条件下,通过定向凝固技术制备了具有对接结构的镍基高温合金单晶铸件,采用实验与有限元模拟相结合的方法,研究了对接平台内缩松缺陷的形成机制,并讨论了抽拉速率对缺陷形成的影响。结果缩松缺陷主要出现在各对接平台的最后凝固区,随着抽拉速率的增大,缩松缺陷的范围有所增大、数量有所增加。结论铸件各平台中上侧位置均形成了缩孔缺陷,这与铸件特殊的对接型几何结构有关;随着抽拉速率的增大,凝固界面的下凹程度增大,平台两侧熔体过早凝固,使平台内部补缩通道受阻,最终导致各平台最后凝固区产生缩松缺陷。The work aims to study the dendritic growth and formation mechanism of solidification defects in the rejoined platforms of Ni-based single crystal superalloys.In this study,the castings of Ni-based single crystal superalloys with rejoined structure were prepared by directional solidification under different withdrawal rates.The formation mechanism of porosity in rejoined platforms was studied by experiment and finite element simulation.The influence of withdrawal rates on the formation of defects was discussed.The results showed that the porosity mainly appeared in the final solidification zone of the rejoined platforms.With the increase of the withdrawal rate,the range and number of porosity increased.Porosity defects form on the upper side of each platform of the casting,which is related to the special geometry of the casting.As the withdrawal rate in-creases,the curvature of the“concavity”at the solidification interface increases,and the melt on both sides of the platform is so-lidified prematurely,obstructing the internal feeding channels of the platform and ultimately leading to porosity defects in the final solidification zone of each platform.

关 键 词：镍基单晶高温合金 对接平台 缩松缺陷 抽拉速率 补缩 

分 类 号：TG132.3[一般工业技术—材料科学与工程]