焊后热处理对5B70铝镁钪合金板材焊接接头组织性能的影响  

Effect of Post-Welded Annealing on Microstructure and Properties of Welding Joint for 5B70 Al-Mg-Sc Alloy Sheet

作　　者：何振波[1,2] 尹志民[1] 陈继强[1] 

机构地区：[1]中南大学材料学院,长沙410083 [2]东北轻合金有限责任公司,哈尔滨150060

出　　处：《航空材料学报》2010年第5期39-43,共5页Journal of Aeronautical Materials

基　　金：总装预研项目(51312010402)

摘　　要：以5B71焊丝为焊接填充材料,对厚度6mm的5B70-H32铝镁钪合金板材进行氩弧焊焊接,之后对焊接接头进行280~340℃/1h焊后处理。采用力学性能测试和显微组织评估方法研究了焊后热处理对5B70铝镁钪合金板材焊接接头组织性能的影响。结果表明,合金焊接接头焊缝区为明显的树枝晶组织,采用焊后退火处理后焊接接头焊缝区枝晶明显减少,晶粒更为均匀,同时基体中析出大量A l3（Sc,Zr）粒子;焊后处理能显著提高5B70铝镁钪合金焊接接头的强度,在280~340℃范围内,焊后处理温度愈高,强度升高愈显著,塑性也有所提高;焊缝区A l3（Sc,Zr）粒子析出强化是焊接接头焊后退火力学性能提高的主要原因。5B70 Al-Mg-Sc alloy sheets with 6 mm thickness at H32 heat treatment condition were welded using 5B71 Al-Mg-Sc welding wire and then the welded joints were annealed at 280～340℃ for 1h.The microstructures and mechanical properties of the welded joints at different condition were analyzed by tensile test,micro-hardness test,OM and TEM.The results show that the welding joints have apparent dendrite grain structure,while after post-welded annealing,the kind of dendrite grain structure disappeared.During post-welded annealing,large amounts of coherent A13（Sc,Zr） particles precipitate and distribute uniformly within the matrix,which increase the strength of the welded joint.At the range of 280～340℃ annealing,the higher the annealing temperature,the higher the strength of the welded joints,and the elongation ratio of welded joints also increased.The A13（Sc,Zr） strengthening precipitates should be responsible for the improvement of mechanical properties of the welded joints with post-welded annealing.

关 键 词：铝镁钪合金 焊后热处理 焊接接头组织与性能 Al3(Sc Zr) 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG407[金属学及工艺—金属材料]