TC4钛合金激光焊接头显微组织及断口分析  

Analysis on Microstructure and Fracture of TC4 Titanium Alloy Laser Welded Joints

作　　者：侯继军[1] 董俊慧[1] 张启良[1] 

机构地区：[1]内蒙古工业大学材料科学与工程学院,内蒙古呼和浩特010051

出　　处：《热加工工艺》2016年第3期35-37,41,共4页Hot Working Technology

基　　金：内蒙古自治区教育厅研究生科研创新资助项目(B20141012805);内蒙古工业大学科学研究项目(X201315)

摘　　要：利用光学显微镜观察了TC4钛合金激光焊接头的显微组织,借助扫描电子显微镜对母材及接头拉伸断口进行了分析。结果表明:靠近熔合线处焊缝晶粒为粗大的柱状晶,晶内组织为针状马氏体α′;焊缝中心晶粒为粗大的等轴晶,晶内组织以小块状α+β、大块状α、层片状魏氏组织和α′为主;近焊缝热影响区组织为α+α′的"筐篮"状组织;过渡区组织由高温β转变形成的α相+少量针状α′+原始(α+β)构成;近母材热影响区组织由高温β转变形成的α相和原始(α+β)构成;母材拉伸断裂形式属于延性断裂,接头拉伸断裂形式属于脆性断裂,具有解理断裂的特征。Optical microscope was used to observe the microstructure of TC4 alloy laser welded joint. With the aid of scanning electron microscope, the tensile fracture of base metal and welded joint was analyzed. The results show that acicular martensite α＂ appears in coarse columnar crystals grains near the weld fusion line. The microstructure in the center of weld seam is coarse equiaxed grains with small block α ＋β, big block α, lamellar widmanstatten microstructure and α＇. The microstructure of heat affected zone closing to weld bead is ＂ basket ＂α＋α＇. The transition zone microstructure consists of α transformed from high-temperature β, small amount of acicular α＂ and original（α＋β）. The microstructure of heat affected zone closing to base metal is composed of α transformed from high-temperature β and original （α＋β）. The tensile fracture of base metal is ductile fracture. The welded joint is cleavage fracture in a brittle fracture.

关 键 词：TC4 激光焊 显微组织 断口 

分 类 号：TG456.7[金属学及工艺—焊接] TG146.23[一般工业技术—材料科学与工程]