均匀化处理工艺对镍基GH4061高温合金热加工性能的影响  

Effect of compositional homogenization on hot workability of Ni-based GH4061 superalloy

作　　者：胥国华 段然[1,2] 王磊 刘杨[3] 孟凡强[4] Guo-hua XU;Ran DUAN;Lei WANG;Yang LIU;Fan-qiang MENG(Gaona Aero Material Co.,Ltd.,Beijing 100081,China;Department of High-temperature Materials,Central Iron and Steel Research Institute,Beijing 100081,China;Key Lab for Anisotropy and Texture of Materials,Ministry of Education,Northeastern University,Shenyang 110819,China;Sino-French Institute of Nuclear Engineering and Technology,Sun Yat-Sen University,Zhuhai 519080,China)

机构地区：[1]北京钢研高纳科技股份有限公司,北京100081 [2]钢铁研究总院高温材料研究所,北京100081 [3]东北大学材料各向异性与织构教育部重点实验室,沈阳110819 [4]中山大学中法核工程与技术学院,珠海519080

出　　处：《Transactions of Nonferrous Metals Society of China》2023年第6期1792-1802,共11页中国有色金属学报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.U1708253,52271126);the Major Projects in Aviation Engines and Gas Turbines,China(No.2017-VI-0002-0071,2019-VI-0020-0136);the financial support from the National Center for Materials Service Safety Foundation,China。

摘　　要：针对镍基GH4061高温合金凝固过程复杂、铸态组织偏析严重、枝晶间生成的大量低熔点第二相、严重降低合金的热加工性能的问题,采用OM、SEM、EPMA和TEM系统研究均匀化处理温度和时间对GH4061合金枝晶偏析、低熔点Laves相等回溶行为及合金热加工性能的影响。结果表明,铸态合金中发生严重的枝金偏析,Nb、Ti和Mo元素枝晶间偏析系数分别高达2.435、1.346和1.200。经1160℃保温20 h均匀化处理后,枝金偏析得到充分消除,Nb元素枝晶间偏析系数降低到1.098;同时,Laves和δ相基本回溶,且无晶界熔化现象;提高热处理温度显著加速成分均匀化与低熔点第二相的回溶速度。高温力学性能研究结果表明,两级均匀化热处理能够有效地提高合金热加工塑性至1150℃;断口分析表明,低熔点的Laves相和δ相的回溶降低了裂纹萌生与断裂的几率,提高了合金的塑性变形能力。Complex solidification process,severe chemical segregation and large amounts of secondary phases with low melting point between dendrites deteriorate the hot workability of as-cast GH4061 superalloy.The effects of the homogenization temperature and time on the dendritic segregation,dissolution behavior of Laves phase with low melting point intermetallic phases and hot workability of the alloy were investigated using OM,SEM,EPMA and TEM.The results show that in the as-cast sample,severe compositional segregation is found among dendritic structures and the highest segregation coefficient of Nb is 2.435,followed by Ti of 1.346 and Mo of 1.200.After homogenization at 1160℃for 20 h,the segregation among dendritic structures has been fully eliminated and the segregation coefficient of Nb declines to 1.098.Meanwhile,Laves anddphases are mostly dissolved and no any localized grain boundary re-melting was observed.Increasing annealing temperature accelerates the speed of chemical homogenization and dissolution of intermetallic compounds.High-temperature mechanical properties testing results demonstrate that two-step homogenization treatment promotes the plasticity up to 1150℃.Fracture analysis reveals that the dissolution of Laves anddphases reduces the probability of crack initiation and fracture,resulting in a good hot workability.

关 键 词：GH4061高温合金 枝晶偏析 LAVES相 热加工性能 

分 类 号：TG132.3[一般工业技术—材料科学与工程]