母材显微组织对激光沉积修复K4169合金液化裂纹敏感性的影响  

Influence of Base Material Microstructure on Liquation Cracks Sensitivity in Laser Deposition Repaired K4169 Alloy

作　　者：钦兰云 王鹤达 李长富 任宇航 王超 杨光 Qin Lanyun;Wang Heda;Li Changfu;Ren Yuhang;Wang Chao;Yang Guang(School of Mechatronic Engineering,Shenyang Aerospace University,Shenyang 110136,Liaoning,China;Key Laboratory of Fundamental Science for National Defense of Aeronautical Digital Manufacturing Process ofShenyang Aerospace University,Shenyang 110136,Liaoning,China)

机构地区：[1]沈阳航空航天大学机电工程学院,辽宁沈阳110136 [2]沈阳航空航天大学航空制造工艺数字化国防重点学科实验室,辽宁沈阳110136

出　　处：《中国激光》2024年第10期302-313,共12页Chinese Journal of Lasers

基　　金：国家重点研发计划(2022YFE122600)。

摘　　要：在对K4169合金母材进行修复前采用不同的工艺进行热处理,以获取两类不同的显微组织,然后对比分析了母材的显微组织分和力学性能,并系统研究了修复试样热影响区液化裂纹的敏感性和产生机制。研究结果显示:在均匀化固溶时效条件下,母材主要由Laves相、δ相以及碳化物组成,修复试样母材与热影响区的平均显微硬度分别为220 HV和210 HV,修复试样的抗拉强度、屈服强度和延伸率分别为870.7 MPa、618.9 MPa和7.7%,断裂位置位于母材。在均匀化热等静压固溶时效条件下,母材主要由δ相以及碳化物组成;修复试样中存在裂纹,裂纹分布在母材一侧,横截面上裂纹的平均长度可达0.68 mm,最大裂纹长度为0.72 mm;热影响区液化裂纹的发生与母材的组织成分、晶粒度密切相关。相较之下,均匀化热等静压固溶时效合金修复试样母材与热影响区的平均硬度都较低,分别为210 HV和200 HV,Laves相和δ相的含量对母材和热影响区的显微硬度均有影响,抗拉强度和屈服强度分别降低了20.3%和38.4%,但延伸率有所升高,断裂位置在热影响区。两种试样都未断在修复区,这是因为修复区的晶粒更细,产生了细晶强化作用。Objective K4169 hightemperature alloys exhibit high strength,plasticity,and heatcorrosion resistance in the middle and lowtemperature ranges and are particularly suitable for manufacturing aircraft engines.The ascast state of the K4169 alloy is prone to severe elemental segregation,resulting in deteriorated welding performance.The presence of liquation cracks in the heataffected zone significantly reduces the safety and operational reliability of the product.To enhance the quality of repairs,laser pretreatment is employed to adjust the composition,structure,and phase distribution of the base material while reducing its strength and hardness to improve the liquation crack sensitivity of the matrix material.However,a systematic study of the prelaser treatment process for K4169 nickelbased hightemperature alloys has not been carried out.In particular,the influence of the base material’s structure on crack initiation mechanisms is not well understood.Therefore,this study emphasizes the necessity of employing pretreatment processes to regulate the K4169 alloy base material before repair,and conducts indepth research on the sensitivity and mechanisms of liquation cracks in the repaired specimen’s heataffected zone.The results of this study have significant implications for the highquality repair of nickelbased hightemperaturealloy components in aerospace.Methods This study employed a homogenization+solution+aging treatment and homogenization+hot isostatic pressing+solution+aging treatment on a K4169 alloy substrate prior to repair,followed by repair experiments using the laser deposition process with synchronized powder feeding for different substrate microstructures.The repaired specimens subjected to the homogenization+solution+aging treatment were denoted LDR,whereas those subjected to the homogenization+hot isostatic pressing+solution+aging treatment were denoted LDRK9.The process parameters included a laser power of 1600 W,scanning speed of 8 mm/s,scanning speed of 1 rad/min,overlap rate of 40%,and laser diame

关 键 词：激光技术 激光沉积修复 K4169合金 修复前热处理 开裂机理 力学性能 

分 类 号：TG146.1[一般工业技术—材料科学与工程]