异质镍基高温合金激光沉积修复开裂机理研究  

Study on Cracking Mechanism of Laser Deposition Repaired HeterogeneousNickel-Based High Temperature Alloy

作　　者：曹越 李长富 于广滨[3] 李勇军 CAO Yue;LI Changfu;YU Guangbin;LI Yongjun(School of Mechanical and El ectrical Engineering,Shenyang Aerospace University,Shenyang 110136,China;Key Laboratory of Fundamental Science for National Defence of Aeronautical Digital Manufacturing Process,Shenyang Aerospace University,Shenyang 110136,China;School of Mechatronics Engineering,Harbin Institute of Technology,Harbin 150001,China;AECC Harbin Dong'an Engine Corporation Limited,Harbin 150066,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 [3]哈尔滨工业大学机电工程学院,黑龙江哈尔滨150001 [4]中国航发哈尔滨东安发动机有限公司,黑龙江哈尔滨150066

出　　处：《热加工工艺》2024年第20期30-36,41,共8页Hot Working Technology

基　　金：国家重点研发计划项目(2022YFE122600);中国航空发动机集团产学研合作项目(HFZL2021CXY025-1);辽宁省国际科技合作计划项目(2023JH2/10700024)。

摘　　要：针对高裂纹敏感性K424镍基高温合金薄壁件难修复现状,采用低裂纹敏感性的GH4169镍基合金粉末在K424高温合金基板上进行激光沉积修复,对过程中产生的裂纹特征和开裂机理进行了研究。结果表明:修复时,裂纹首先在基材的热影响区萌生,然后分别向沉积区和基材内部扩展。这些裂纹呈现出曲折的沿晶界开裂特征,具有典型的液化裂纹形貌。经形貌分析和成分分析发现,晶界上的液膜主要来源于晶界上较大尺寸的在激光作用下未完全熔解的γ'相与γ相发生共晶反应,在热作用下形成液膜。此外,碳化物、硼化物等低熔点相在高温下熔解发生富集,促进了高温下液膜的形成。通过Simufact Welding软件所建立的数值模型验证了修复过程中的应力场和温度场,其中热影响区附近存在较大的应力场,是裂纹形成的驱动力。因此,在热影响区内,晶界上液膜的产生和较大应力的存在为液化裂纹的形成提供了条件。In view of repair difficulty of the high crack sensitivity K424 nickel-based superalloy thin wall piece,the low crack sensitivity GH4169 nickel-based superalloy powder was employed in deposition repairing on K424 superalloy substrate.The characteristics of cracks and the mechanisms of cracking during this process were studied.The results show that during the repair process,cracks initially initiate in the heat-affected zone of the base material,subsequently extending towards both the depositional zone and the interior of the base material.These cracks exhibit a sinuous intergranular cracking pattern,displaying typical liquation crack morphology.Morphological and compositional analyses indicate that the liquid film on the grain boundaries primarily originates from the eutectic reactions of incomplete melting larger-sizedγ'phases andγphases under laser irradiation,resulting in the formation of the liquid film under thermal conditions.Additionally,low-melting-point phases such as carbides and borides melt and accumulate at high temperatures,promoting the formation of liquation films at elevated temperatures.The numerical model established with Simufact Welding software validates the stress and temperature fields during the repair process,revealing significant stress fields near the heat-affected zone as the driving force for crack formation.Therefore,in the heat affected zone,the formation of liquid film on the grain boundary and the existence of large stress provide conditions for the formation of liquation cracks.

关 键 词：激光技术 激光沉积修复 镍基高温合金 液化裂纹 液膜 应力 

分 类 号：TG146.15[一般工业技术—材料科学与工程] TG456.7[金属学及工艺—金属材料]