液态金属冷却工艺下籽晶成分对单晶生长的影响  

Effect of Seed Composition on Single Crystal Growth During LMC Process

作　　者：黄亚奇 张爱民 张金 郑伟[1] 申健[1] 王栋[1] 谢光[1] 卢玉章[1] HUANG Ya-qi;ZHANG Ai-min;ZHANG Jin;ZHENG Wei;SHEN Jian;WANG Dong;XIE Guang;LU Yu-zhang(Institute of Metal Research Chinese Academy of Sciences,Shenyang 110023,Liaoning,China;Chengdu Hehong Technology Company Limited,Chengdu 610100,Sichuan,China;State Key Laboratory of Advanced Casting Technologies,China Academy of Machinery Shenyang Research Institute of Foundry Co.,Ltd.,Shenyang 110022,Liaoning,China)

机构地区：[1]中国科学院金属研究所高温结构材料研究部,辽宁沈阳110023 [2]成都和泓科技股份有限公司,四川成都610100 [3]中国机械总院集团沈阳铸造研究所有限公司,高端装备铸造技术全国重点实验室,辽宁沈阳110022

出　　处：《铸造》2024年第12期1652-1658,共7页Foundry

基　　金：国家重点研发计划项目(2021YFB3702900、2021YFA1600603和2022YFB3705000);哈尔滨工业大学金属精密热加工国家级重点实验室项目(JCKYS2022603C008);辽宁省科学技术计划(2022JH2/101300226);国家自然科学基金项目(52271042、U2141206和U2241283);航空发动机及燃气轮机基础科学中心项目(P2022-C-IV-001-001);国家科技重大专项项目(P2021-AB-IV-001-002、J2019-IV-0006-0074和J2019-VI-0010-0124)。

摘　　要：利用单晶高温合金SX1、SX2分别作为籽晶和铸造材料,进行了LMC工艺下籽晶法控制单晶高温合金晶体取向的浇注试验和数值模拟,并对籽晶和铸件进行了解剖分析。结果表明:当籽晶和铸造材料为同一成分时,可以获得完整的单晶铸件,并且籽晶与单晶铸件取向一致。当籽晶和铸造材料为不同成分时,如果籽晶的液相线高于铸造材料的液相线,则获得完整的单晶铸件,并且籽晶与单晶铸件取向一致;反之,如果铸造材料的液相线高于籽晶的液相线,则会在籽晶重熔界面处产生大量的杂晶形核,并在纵向温度梯度下长大为定向柱晶,无法获得完整的单晶铸件。数值模拟结果表明这可能是由于合金浇注后,在抽拉过程中,上部铸造材料由于液相线较高,在籽晶重熔界面处优先凝固,导致重新形核,形成定向柱晶。因此,在利用籽晶法进行单晶铸件取向控制时应当保证籽晶的液相线等于或者高于铸造材料的液相线,才能获得完整的单晶组织,并精确控制取向。Liquid Metal Cooling(LMC)directionally solidified(DS)experiment and numerical simulation were conducted based on seed method using single-crystal superalloy(SX)SX1 and SX2 as materials.The seeds and castings were cut to observe the microstructure of the dendrites.It was found that the complete SX casting can be achieved with the same orientation between casting and seed when the same materials were used in casting and seed.In case of different composition between seed and casting,the complete SX casting can also be obtained with preferred<001>orientation if the liquidus of seed was higher than that of casting.Otherwise DS structure would be found from stray grain formed at meltback interface of seed,which indicated that SX growth was failed.The numerical simulation results show that casting material with higher liquidus than that of seed can solidify preferentially from meltback interface and DS structure formed subsequently during withdrawing.Therefore,it is necessary for orientation control to ensure that the liquidus line of seed is equal to or higher than that of casting during seed method.

关 键 词：液态金属冷却 单晶高温合金 取向控制 籽晶法 

分 类 号：TG132.3[一般工业技术—材料科学与工程]