电子束局部热处理对TC4钛合金焊接接头组织和性能的影响  

Effects of local heat treatment by electron beam on microstructure and properties of TC4 titanium alloy welded joint

作　　者：胡美娟[1] 刘金合[1] 康文军[1] 阮成勇[1] 

机构地区：[1]西北工业大学材料学院,西安710072

出　　处：《焊接学报》2008年第2期104-107,共4页Transactions of The China Welding Institution

摘　　要：通过对14.5mm厚TC4钛合金平板电子束焊接接头的局部热处理,研究了电子束局部热处理对钛合金电子束焊接接头组织、硬度和拉伸性能的影响。结果表明,电子束局部热处理后扫描区内的母材组织晶粒粗化长大,α相在原始β晶界处长大的同时,以层片状或针状的α形态向β晶内生长。局部热处理后冷却速度的降低使焊缝组织中的针状马氏体在分解析出β相的同时转变为α相,变短变厚的α相相互交错排列。另外,局部热处理消除了焊缝和热影响区的硬度突变。同焊后状态相比,局部热处理后焊接接头的整体性能沿焊缝垂直方向得到了均衡和提高,拉伸试样的断裂位置由焊后状态时的热影响区和母材的交界处转移到未经历热处理的母材区域。The local heat treatment by electron beam on welded joint of 14.5 mm thick TC4 titanium alloy plate was carried out.Its influence on the microstructure,hardness and tensile properties of electron beam welded joint was investigated.Experimental results show that the crystal grain size of the base metal within the scanning field of local heat treatment grows explicitly after local heat treatment.While it is precipitated and grows along prior-β grain boundary,α phase with a lamellar or acicular appearance grows into β grain from grain boundary.Because local heat treatment decreased the cooling velocity of weld metal,the acicular martensite decomposes β phase and transforms to coarser and shorter α phase,which shows an interwoven pattern.In addition,the hardness profile becomes smoother and differences between heat-affected zone and weld come to be almost eliminated.Integral properties of welded joint are equalized and increased along weld cross-section after local heat treatment.Fracture position of tensile test specimen shifts from the common zone between heat affected zone and base metal to parent metal without undergoing heat treatment.

关 键 词：局部热处理 电子束焊接 TC4钛合金 显微组织 拉伸性能 

分 类 号：TG456.3[金属学及工艺—焊接]