摘要
采用超声冲击方法对MB8镁合金十字接头焊趾处进行超声冲击处理,对比测试焊态及冲击处理态接头的表层组织和疲劳性能。结果表明:超声冲击处理可以在MB8镁合金焊接接头表面获得纳米晶组织。在循环寿命为2×106条件下,焊态试样的条件疲劳强度为32.07MPa,冲击处理态试样的条件疲劳强度为41.88MPa,提高了30.59%。未冲击接头疲劳断裂大多发生在焊缝缺陷处,冲击处理后的接头则发生在热影响区。超声冲击处理不仅可以大幅提高MB8镁合金十字接头的疲劳寿命,还可以改变接头疲劳断裂位置。此外,热影响区也是MB8镁合金十字接头疲劳断裂的薄弱区域,这与热影响区晶粒粗大有很大的关系。
Surface treatment was carried out on the weld toe of MB8 magnesium alloy welded joints with ultrasonic impact treatment(UIT)method.The Surface microstructure and the fatigue property of treated and as-welded MB8 magnesium alloy welded joints were investigated.The experimental results show that after ultrasonic impact treatment,nano-crystalline microstructure is obtained by UIT method.Under the condition of the cycle life of 2×10 6,the conditional fatigue limit of as-welded joints is 32.07MPa,and the conditional fatigue limit of treated joints is 41.88MPa,which is increased by 30.59%than that of as-welded.The fatigue fracture of as-welded joints occurs mostly in the defects of weld zone,and the fatigue fracture of treated joints occurs mostly in the heat-affected zone.The ultrasonic impact treatment can not only increase the fatigue life of the joints,but also can change the fracture position of the samples.In addition,the heat affected zone is also a weak area of the fatigue fracture of the MB8 magnesium alloy cross joints,which is greatly related with the coarse grains in the heat affected zone.
作者
何柏林
江明明
于影霞
李力
HE Bo-lin;JIANG Ming-ming;YU Ying-xia;LI Li(School of Materials Science&Engineering,East China Jiaotong University,Nanchang 330013,China)
出处
《材料工程》
EI
CAS
CSCD
北大核心
2018年第10期70-76,共7页
Journal of Materials Engineering
基金
国家自然科学基金项目(51265013)
江西省自然科学基金项目(20151BAB206007)
江西省工业支撑重点项目(20161BBE50072)
关键词
超声冲击
MB8镁合金
十字接头
疲劳性能
断口形貌
ultrasonic impact
MB8 magnesium alloy
cross joint
fatigue property
fracture morphology