热腐蚀对K444合金高周疲劳的影响研究  

Effects of Thermal Corrosion on High Cycle Fatigue Strength of K444 Alloy

作　　者：李明亮 贾旭 凌晨 于连旭 于苏洋 江荣 宋迎东[1,5] Mingliang;JIA Xu;LING Chen;YU Lianxu;YU Suyang;JIANG Rong;SONG Yingdong(College of Energy and Power Engineering,Nanjing University of Aeronautics&Astronautics,Nanjing 210016,China;College of General Aviation and Flight,Nanjing University of Aeronautics&Astronautics,Liyang 213300,China;Nanjing Guore Metal Materials Research Institute Co.,Ltd.,Nanjing 211135,China;Science and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Beijing 100095,China;Harbin Engineering University,Harbin 150001,China)

机构地区：[1]南京航空航天大学能源与动力学院,南京210016 [2]南京航空航天大学通用航空与飞行学院,溧阳213300 [3]南京国重新金属材料研究院有限公司,南京211135 [4]中国航发北京航空材料研究院先进高温结构材料重点实验室,北京100095 [5]哈尔滨工程大学,哈尔滨150001

出　　处：《南京航空航天大学学报(自然科学版)》2025年第2期327-336,共10页Journal of Nanjing University of Aeronautics & Astronautics

基　　金：航空发动机及燃气轮机基础科学中心重大项目(P2022-A-Ⅲ-003-001);江苏省优秀青年基金(BK20220136)。

摘　　要：针对热腐蚀致燃气轮机涡轮叶片高周疲劳(High cycle fatigue,HCF)失效问题,使用NaCl+Na2SO4盐对涡轮叶片用K444合金进行热腐蚀,采用SEM、EDS及纳米压痕仪研究了热腐蚀层的微观组织、成分和硬度,基于逐级加载法研究了热腐蚀对K444合金HCF强度的影响。研究结果表明热腐蚀引起了K444合金的氧化与硫化,硫化层位于氧化层下,同时在与硫化层毗邻的基体中存在γ'相贫乏区。随着热腐蚀时长的增加氧化层逐渐增厚,硫化层厚度出现先增大后减小的趋势,纳米压痕分析得到的硬度顺序为氧化层>基体>硫化层。热腐蚀加速了K444合金的疲劳裂纹萌生,使得K444合金缺口试样的疲劳强度降低了9.68%~23.97%。This article focuses on the problem of high cycle fatigue(HCF)failure of gas turbine blades caused by hot corrosion.NaCl+Na2SO4 salt mixture is used for hot corrosion of K444 alloy for turbine blades.The microstructure,composition,and hardness of the hot corrosion layer are studied using SEM,EDS,and nanoindentation.The effect of hot corrosion on the HCF strength of K444 alloy is studied based on the stepwise loading method.The research results indicate that hot corrosion causes oxidation and sulfurization of the K444 alloy,with the sulfurization layer located below the oxidation layer,and there is aγ'depletion zone in the matrix adjacent to the sulfurization layer.As the duration of hot corrosion increases,the oxide layer gradually thickens,and the thickness of the sulfide layer shows a trend of first increasing and then decreasing.The hardness order obtained from nanoindentation analysis is the oxide layer>matrix>sulfide layer.Hot corrosion accelerates the initiation of fatigue cracks in K444 alloy,resulting in a decrease of fatigue strength of K444 alloy notched specimens by 9.68%-23.97%.

关 键 词：镍基高温合金 氧化 热腐蚀 高周疲劳 裂纹萌生 

分 类 号：O346.2[理学—固体力学]