GH4169旋转摩擦焊飞边成形机理研究  

Flash Formation Mechanism During Rotary Friction Welding of GH4169 Superalloy

作　　者：金峰 熊江涛[1] 石俊秒 郭德伦[3] 李京龙[2] JIN Feng;XIONG Jiangtao;SHI Junmiao;GUO Delun;LI Jinglong(State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China;Shaanxi Key Laboratory of Friction Welding Technologies,Northwestern Polytechnical University,Xi’an 710072,China;AVIC Manufacturing Technology Institute,Beijing 100024,China)

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072 [2]西北工业大学摩擦焊接陕西省重点实验室,西安710072 [3]中航工业北京航空制造工程研究所,北京100024

出　　处：《材料导报》2020年第10期10144-10149,共6页Materials Reports

基　　金：国家自然科学基金(51575451,51475376)。

摘　　要：本文以Φ25 mm的GH4169实心棒为母材展开连续驱动旋转摩擦焊实验,在缩短量5 mm、焊接压力200 MPa、转速500~2500 r/min条件下,结合高速摄像机、红外热成像仪获得缩短速度演变及界面温度,通过光镜、扫描电镜、EBSD手段表征接头形貌演变,利用Matlab表征界面产热分布,揭示飞边成形机理。结果表明,GH4169旋转摩擦焊飞边随转速增大,依次呈现为光滑、表面弧纹、开裂形貌。800 r/min是一个临界转速判据,当转速小于800 r/min时,飞边呈光滑形貌;当转速介于800~1500 r/min时,飞边出现弧纹;当转速不低于1500 r/min时,飞边显著开裂。光滑形貌对应于较慢的飞边生长速度和较长的生长时间,飞边金属在变形、挤出界面的同时,有充分的时间再结晶软化,使表面流铺光滑;弧纹和开裂形貌对应于飞边在快速和较短时间内生长,再结晶来不及完成而发生加工硬化开裂。不同的飞边形貌,其形成机理不同:光滑形貌是塑性环(塑化金属)在界面中径到边缘处(0.43 R^R)形核,随后铺展并挤出界面发生飞边连续生长现象,即飞边是塑化金属均匀流铺、挤出的结果;弧纹和开裂形貌对应于塑性环形核在界面内侧(0~0.43 R),在界面压力的作用下被封闭在界面内部无法挤出,其飞边的形成,是界面持续摩擦使温度达到焊接温度后的变形挤出结果,即飞边是焊接后期界面金属快速镦粗变形形成的。不同的飞边形貌,对接头的静载拉伸强度分布影响不大,但影响到接头外缘延伸率。光滑、弧纹、开裂形貌,分别对应于接头外缘延伸率17%、9%、6%,相应的接头延伸率不均匀性从8%上升至50%、66%。In this work,continuous-drive rotary friction welding was conducted on GH4169 rods in diameter ofΦ25 mm to investigate the flash formation mechanism.The welding parameters were set as burn-off length 5 mm,welding pressure 200 MPa and rotation speed ranged as 500-2500 r/min.The high-speed camera was installed to monitor the burn-off rate;whereas the infrared camera to collect the surface temperature of the joint.The joints were cut for interface morphology and microstructure observation by OM,SEM and EBSD.On the other hand,the calculation on friction heat liberation was modeled and conducted in Matlab environment,which is correlated by the experiment of interim stops on welding process that were carried out to reveal the transient morphology of the joint.The results tell that,the joint shows the flash appearance as smooth,‘arcuate microcracked’and cracked consequently as the rotation speed is increased.The rotation speed was found a criterion at about 800 r/min,below which the joint presents smooth flash.When the rotation speed is around 800-1500 r/min and over 1500 r/min,‘arcuate microcracked’and cracked flash occur consequently.Smooth flash corresponds to slower growth speed of the flash with longer growth time,which provides the conditions for recrystallization and softening when the metal is extruded to form flash.Whereas,‘arcuate microcracked’and cracked flash correspond to faster speed and shorter time,where recrystallization has not been completed before work hardening and cracking during the flash formation.Moreover,different flash appearances correspond to different formation mechanisms.Smooth flash is the result of uniform flow and extrusion of plasticized metal,which is originated from the corona-bond initiating at middle to the edge(0.43 R-R)of the interface and then extending.Whereas,‘arcuate microcracked’and cracked flash are formed under rapid forging process of interface metal at welding temperature due to the lack of plasticized metal,which initiates at inner side of the interface

关 键 词：镍基高温合金 GH4169 旋转摩擦焊 飞边形貌 塑性环 接头性能 

分 类 号：TG453[金属学及工艺—焊接]