MB8镁合金焊接接头超高周疲劳性能  

Ultra high cycle fatigue properties of MB8 magnesium alloy welded joint

作　　者：谢学涛 何柏林 邓海鹏 

机构地区：[1]华东交通大学机电与车辆工程学院,江西南昌330013

出　　处：《兵器材料科学与工程》2018年第1期20-23,共4页Ordnance Material Science and Engineering

基　　金：国家自然科学基金(51265013);江西省自然科学基金(20151BAB206007);江西省工业支撑重点项目(20161BBE50072)

摘　　要：为提高镁合金焊接接头的超高周疲劳寿命及其安全可靠性,采用机械打磨除去MB8镁合金焊接接头余高,利用超声疲劳试验机来探究MB8镁合金焊接接头超高周疲劳性能。结果表明:MB8镁合金焊接接头的S-N曲线在2.0×10~8周左右时会出现平台,说明其存在疲劳极限;当疲劳寿命小于2.0×10~8周,S-N曲线呈连续下降趋势,疲劳寿命随着载荷的降低而增加;疲劳失效试样都断裂在试样的中间焊缝部位,疲劳断口可以分成疲劳源区,柱状晶扩展区、过渡扩展区、粗晶扩展区、瞬断区5个区域。In order to increase the ultra high cycle fatigue life of magnesium alloy welded joints and its safety reliability,the mechanical grinding was used to remove the reinforcement of MB8 magnesium alloy welded joints,and the ultrasonic fatigue testing machine was used to investigate the ultra high cycle fatigue properties of MB8 magnesium alloy welded joints.The results show that the S-N curve of the MB8 magnesium alloy welded joint,in the 2×10~8 cycles,the platform will appear,which shows the fatigue limit of the MB8 magnesium alloy welded joints.When the fatigue life is less than 2×10~8 cycles,the S-N curve shows a continuous downward trend,and the fatigue life increases with the decrease of the load.The fatigue failure specimens are broken in the middle weld part of the specimen.Fatigue fracture can be divided into five regions：fatigue source region,columnar crystal extension zone,transition extension zone,coarse grain expansion zone and transient zone.

关 键 词：焊接接头 MB8镁合金 超高周疲劳 S-N曲线 

分 类 号：TG113[金属学及工艺—物理冶金]