真空热循环作用下LF6合金焊接接头的拉伸性能和微观组织  

Tensile properties and microstructure of LF6 alloy welded joint subjected to thermal cycling

作　　者：赵慧杰[1] 何松[1] 耿洪滨[1] 

机构地区：[1]哈尔滨工业大学材料科学与工程学院,哈尔滨150001

出　　处：《焊接学报》2004年第1期33-35,39,共4页Transactions of The China Welding Institution

基　　金：国家重点基础研究规划项目 (973 ) (Q19990 65 0 )

摘　　要：采用精密多功能低温静载材料实验机、热循环试验装置、透射电镜和扫描电镜 ,系统研究了真空热循环条件下LF6合金焊接接头的拉伸性能和微观组织 ,分析讨论了真空热循环对LF6合金焊接接头的影响规律。研究结果表明 ,在循环 30 0周次范围内 ,真空热循环可改善LF6合金焊接接头的拉伸性能 ,使其强度和塑性均得到提高。热循环对焊接接头拉伸性能具有影响 ,并同循环次数有关。初始循环时 ,由于位错不断增殖 ,使得LF6合金焊接接头的强度和塑性增加较快 ;经热循环 70周次后 ,接头的强度和塑性均达到最高值 ;循环次数继续增加 ,强度和塑性开始下降 ,这可能与晶内位错密度降低、晶界处形成位错墙有关。The tensile properties and microstructure of LF6 aluminum alloy welded joint under conditions of vacuum and thermal cycling have been studied by means of precise multifunction material testing system, constraint thermal cycling system, transmission electron microscope and scanning electron microscope so as to investigate the influence of thermal cycling on the tensile behavior of LF6 alloy welded joint. The results show that the vacuum and thermal cycling could increase the strength and elongation of the LF6 alloy welded joint. Both the strength and elongation are increased after thermal cycling, and the improvement that is influenced by numbers of thermal cycling is obviously for the welding joint. At the initial stage of thermal cycling, the strength and elongation of the LF6 alloy welded joint increase fast as a result of the generation of dislocation. The strength and elongation of the LF6 alloy welded joint reach their maximum values after cycling for 70 cycles. After that, the strength and elongation of the LF6 alloy welded joint decrease with proceeding of thermal cycling, which is resulted from the decrease of dislocation density within grain and formation of dislocation walls at the grain boundaries.

关 键 词：真空热循环 LF6合金 焊接接头 拉伸性能 微观组织 

分 类 号：TG457.14[金属学及工艺—焊接] TG146.21[一般工业技术—材料科学与工程]