保温时长对DD5/FGH98扩散焊接头组织及力学性能的影响  

Effect of Holding Time on Microstructure and Mechanical Properties of DD5/FGH98 Diffusion Bonded Joint

作　　者：张鑫 钟陈康 田富强[1] 石俊秒 孙现军 ZHANG Xin;ZHONG Chenkang;TIAN Fuqiang;SHI Junmiao;SUN Xianjun(School of Mechanical and Power Engineering,East China University of Science and Technology,Shanghai 200237,China;Xinghua Power Supply Branch of State Grid Jiangsu Electric Power Company,Jiangsu Xinghua 225700,China;School of Materials Science and Engineering,Northwestern Polytechnical University,Xi'an 710072,China)

机构地区：[1]华东理工大学机械与动力工程学院,上海200237 [2]国网江苏省电力有限公司兴化市供电分公司,江苏兴化225700 [3]西北工业大学材料学院,西安710072

出　　处：《精密成形工程》2024年第10期139-146,共8页Journal of Netshape Forming Engineering

摘　　要：目的为优化焊接工艺参数,探究不同保温时长对DD5/FGH98固相扩散焊接头组织和性能的影响。方法采用高熵合金和镍箔作为复合中间层,通过固相扩散焊方式连接DD5单晶高温合金和FGH98粉末高温合金。在1130℃、4 MPa的压力条件下,进行不同保温时长的焊接。焊接完成后,通过多种表征手段观察接头的微观组织,并通过剪切实验确定接头的性能。结果从微观组织上看,随着保温时间的延长,中间层中高熵合金晶粒长大,FGH98和DD5近焊缝处的γ′相溶解变小,DD5侧母材在高温高压下发生严重的筏化。母材与中间层的元素扩散更加充分。在力学性能方面,保温时间的延长导致中间层硬度降低,与基材硬度差距增加,接头剪切强度逐渐降低。在1130℃、4 MPa条件下,保温1 h的接头强度最高,达到650 MPa。保温1~4 h试样的剪切断裂位置在高熵中间层;保温6 h试样的断裂位置在镍箔区域。结论保温时长影响接头的微观结构和力学性能。在一定焊接温度下,实现完全键合的接头的剪切强度会随着保温时长的延长而降低。The work aims to optimize the bonding process parameters,and investigate the effect of holding time on the microstructure and properties of the DD5/FGH98 solid-state diffusion bonded joint.A high-entropy alloy and nickel foil were used as a composite interlayer to connect the DD5 single-crystal superalloy and FGH98 powder superalloy through solid-state diffusion bonding.The bonding was conducted at 4 MPa and 1130℃with different holding time.After bonding,the microstructure of the joints was observed with various characterization techniques,and the performance was determined through shear tests.From a microstructural perspective,as holding time increased,the grain size of the high-entropy alloy in the interlayer grew,and theγ'phase near the weld in FGH98 and DD5 dissolved and became smaller.Theγ'phase in DD5 experienced significant rafting under high temperature and pressure.Element diffusion between the base material and the interlayer became more sufficient.In terms of mechanical properties,the increase in holding time decreased the hardness of the interlayer,and increased the hardness difference between the interlayer and the base material.And the shear strength of the joint gradually decreased as the holding time increased.At 1130℃and 4 MPa,the joint strength reached its peak(650 MPa)with a holding time of 1 h.For samples held for 1-4 h,shear fracture occurred in the high-entropy interlayer;For the sample held for 6 h,fracture occurred in the nickel foil region.In conclusion,the holding time influences the joint's microstructure and mechanical properties.The shear strength of fully bonded joints decreases with the increase of holding time at a certain welding temperature.

关 键 词：扩散连接 保温时长 DD5 FGH98 高熵合金中间层 

分 类 号：TG456.9[金属学及工艺—焊接]