新型定向凝固镍基高温合金DZ445中γ'相在高温下的演变规律  

Evolution Law ofγ'Precipitates in New Directionally Solidified Nickel-Base Superalloy DZ445 at High Temperatures

作　　者：牛倩 张鹏[2] 李娇[3] 巩秀芳[4] 宋小龙(导师)[1] NIU Qian;ZHANG Peng;LI Jiao;GONG Xiufang;SONG Xiaolong(State Key Laboratory for Mechanical Behavior of Materials,Xi'an Jiaotong University,Xi'an 710049,China;R&D Center,Xi'an Thermal Power Research Institute Co.,Ltd.,Xi'an 710054,China;Instrumental Analysis Center,Xi'an Jiaotong University,Xi'an 710049,China;State Key Laboratory for Long-Life High Temperature Materials,Dongfang Turbine Co.,Ltd.,Deyang 618000,China)

机构地区：[1]西安交通大学,金属材料强度国家重点实验室,西安710049 [2]西安热工研究院有限公司,清洁低碳热力发电国家工程研究中心,西安710054 [3]西安交通大学大型仪器设备共享实验中心,西安710049 [4]东方汽轮机有限公司,长寿命高温材料国家重点实验室,德阳618000

出　　处：《机械工程材料》2023年第3期12-18,共7页Materials For Mechanical Engineering

基　　金：陕西省自然科学基础研究计划项目(2022JQ-314,2022JQ-460);四川省软科学研究计划项目(2020JDR0383);华能集团重点科技项目(HNKJ20-41)。

摘　　要：通过对新型定向凝固镍基高温合金DZ445进行800~900℃热暴露试验,研究了合金中γ'强化相在高温下的演变规律。结果表明:高温下γ'相的长大受基体元素扩散控制,长大动力学遵循Lifshitz-Slyozov-Wagner熟化规律,扩散激活能为305 kJ·mol^(-1);合金组织稳定,即使是在900℃热暴露10000 h,γ'相颗粒的平均尺寸也只增大至(928±14)nm,在800~900℃下热暴露10000 h时γ'相体积分数保持在50%上下,未观察到拓扑密堆相析出;在850,900℃热暴露过程中,γ'相形貌由类球状向立方或四方块状转变,这种转变与颗粒尺寸和晶格错配度有关。Evolution law ofγ'strengthening precipitates at high temperatures in a new directionally solidified nickelbase superalloy DZ445 was studied by thermal exposure tests at 800-900℃.The results show that at high temperatures,the growth ofγ'precipitates was controlled by diffusion of matrix elements,and the growth kinetics followed the Lifshitz-Slyozov-Wagner ripening law;the diffusion activation energy was 305 kJ·mol^(-1).The microstructure of the alloy was stable.Even after thermal exposure at 900℃for 10000 h,the average particle size ofγ'precipitates only increased to(928±14)nm.The volume fractions ofγ'precipitates remained about 50%in thermal exposure at 800-900℃for 10000 h,and no topologically close-packed phase was observed.During thermal exposure at 850℃and 900℃,the shape ofγ'precipitates changed from spheroidal to cubic or tetragonal,which was related to the particle size and lattice mismatch.

关 键 词：燃气轮机 定向凝固 镍基高温合金 组织稳定性 粗化动力学 

分 类 号：TG132.32[一般工业技术—材料科学与工程]