抽拉速率对定向凝固柱晶DZ4125高温合金组织及偏析行为的影响  

Effects of Withdrawal Rate on Microstructure and Segregation Behavior of Directionally Solidified Column Crystal DZ4125 Superalloy

作　　者：张相龙 徐莽 耿小奇 刘国怀[1] 王晔[2] 王昭东[1] 郭景杰[3] ZHANG Xianglong;XU Mang;GENG Xiaoqi;LIU Guohuai;WANG Ye;WANG Zhaodong;GUO Jingjie(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;College of Materials Science and Engineering,Harbin University of Science and Technology,Harbin 150001,China;School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819 [2]哈尔滨理工大学材料科学工程学院,黑龙江哈尔滨150001 [3]哈尔滨工业大学材料科学工程学院,黑龙江哈尔滨150001

出　　处：《热加工工艺》2024年第3期114-118,123,共6页Hot Working Technology

基　　金：国家自然科学基金项目(52071065);中央高校基本科研业务费项目(N2007007);国家重点研发计划项目(2016YFB0301201)。

摘　　要：采用Bridgman定向凝固法制备了DZ4125定向凝固高温合金,研究抽拉速率对DZ4215合金显微组织及偏析行为的影响。结果表明,随着抽拉速率的增加,合金中一次和二次枝晶间距逐渐减小;γ'相尺寸逐渐减小,且形貌由不规则立方体状、蝴蝶状向规则立方体状转变;枝晶间γ'相尺寸和数量均高于枝晶干处的。碳化物和γ+γ'共晶组织主要分布于枝晶间区域,且随着抽拉速率的提高,碳化物形貌从骨架状逐渐向长条状、块状转变,分布更加弥散、均匀。在定向凝固DZ4125合金中,Co和W为正偏析元素,Al、Ti、Ta、Mo为负偏析元素。随着抽拉速率的增加,正偏析元素的偏析程度降低,负偏析元素的偏析程度增加。The directionally solidified column crystal DZ4125 superalloy was prepared by means of Bridgman directional solidification.The influences of withdrawal rate on the microstructure and segregation behavior were studied.The results show that with increase of withdrawal rate,the primary and secondary dendrite spacing in the alloy gradually decreases;theγ'phase size gradually decreases,and the morphology changes from irregular cube and butterfly to regular cube;the size and amount ofγ'phase in the interdendrite are higher than those of dendritic arm.Theγ+γ'eutectics and carbides are mostly distributed in the interdendritic areas.With the increase of withdrawal rate,the morphology of carbides gradually changes from skeleton form into strip or small block,and the distribution is more dispersed and uniform.In directionally solidified DZ4125 superalloy,the Co and W are positive segregation elements and Al,Ti,Ta and Mo are negative segregation elements.With the increase of withdrawal rate,the segregation degree of positive segregation elements decreases,and the segregation degree of negative segregation elements increases.

关 键 词：定向凝固 镍基高温合金 抽拉速率 微观组织 偏析行为 

分 类 号：TG244.3[金属学及工艺—铸造]