摘要
针对定向凝固DSM11服役涡轮叶片显微组织损伤和性能退化问题,亟需开展亚固溶恢复热处理工艺研究。本研究参考真实服役DSM11叶片的损伤组织,以980℃热暴露500 h定向凝固DSM11合金为研究对象,研究不同亚固溶恢复热处理工艺对损伤组织和性能的影响。结果表明:采用1180℃/2 h固溶结合1120℃/2 h/AC+850℃/24 h/AC恢复热处理制度时,可以获得约23%、尺寸为270 nm左右的二次γ′相和约17%粗大γ′相的双态组织。同时,热暴露过程形成的晶界M23C6型碳化物全部回溶,晶界γ′膜厚度降低。若直接进行1120℃时效处理,晶界M23C6型碳化物也能发生溶解,但晶界γ′膜厚度几乎不发生变化。二次γ′相的尺寸和体积分数与固溶温度和固溶后冷却速度密切相关。炉冷得到的二次γ′相尺寸大于空冷,1160℃固溶时得到的二次γ′相在随后的时效过程中全部溶解,不会被保留。经过1180℃/2 h/AC+1120℃/2 h/AC+850℃/24 h/AC恢复热处理后,热暴露损伤DSM11合金980℃/220 MPa的持久寿命由18 h恢复至24 h,达到标准热处理态的86%。一定含量重新析出的二次γ′相对合金力学性能的恢复起主要作用。
In view of the microstructure damage and property degradation of directionally solidified DSM11 service turbine blades,it is urgent to study the partial-solution rejuvenation heat treatment.In this study,the effects of different recovery heat treatments on the microstructure and mechanical properties of DSM11 superalloy are studied by using alloys after thermal exposure at 980℃for 500 h with reference to the microstructure of DSM11 blade in real service condition.The results show that bimodal microstructures of 23%secondaryγ′phase with the size of approximately 270 nm and 17%coarse degradedγ′phase can be obtained by 1180℃/2 h solution combined with 1120℃/2 h/AC+850℃/24 h/AC recovery heat treatment.Meanwhile,the M23C6 carbides at the grain boundary,which are formed during the thermal exposure,are also dissolved.Andγ′films on the grain boundary are also partially dissolved.Although the M23C6 carbides at the grain boundary can also be dissolved by direct aging at 1120℃without solution heat treatment,theγ′film on the grain boundary changes slightly.The size and volume fraction of the secondaryγ′phase are closely related to the solution temperature and the cooling rate after the solution.The secondaryγ′phase size obtained by furnace cooling is larger than that obtained by air cooling.The secondaryγ′phase obtained at 1160℃solution treatment is completely dissolved in the subsequent aging process and will not be retained in the final.After 1180℃/2 h/AC+1120℃/2 h/AC+850℃/24 h/AC rejuvenation heat treatment,the creep life of degraded DSM11 superalloy is recovered from 18 h to 24 h,which is about 86%of that in standard heat treatment.A certain amount of the reprecipitated secondaryγ′phases play an important role in the recovery of mechanical properties.
作者
周强
华小雨
黄春蓉
郑为为
ZHOU Qiang;HUA Xiaoyu;HUANG Chunrong;ZHENG Weiwei(State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China;Guiyang AECC Power Precision Casting Co.,LTD.,Guiyang 561113,China)
出处
《材料工程》
北大核心
2025年第6期12-23,共12页
Journal of Materials Engineering
基金
国家科技重大专项项目(J2019-Ⅶ-0010-0150)。
关键词
亚固溶恢复热处理
定向凝固DSM11合金
双态组织
力学性能
partial-solution rejuvenation heat treatment
directionally solidified DSM11 superalloy
bimodal microstructure
mechanical property
作者简介
通讯作者:郑为为(1972-),女,副研究员,博士,研究方向为高温金属结构材料成分、制备工艺、组织与性能的关系,高温金属结构材料的服役损伤评价方法,金属材料的塑性变形机理,高温蠕变疲劳行为与机制,联系地址:北京市海淀区学院路30号北京科技大学新金属材料国家重点实验室(100083),E-mail:zhengww@skl.ustb.edu.cn。
