焊前热处理对TC4-DT钛合金电子束焊接接头组织的影响  

Effects of pre-welding heat treatment on microstructure of TC4-DT electron beam welded joint

作　　者：房卫萍[1,2] 史耀武[1] 毛智勇[2] 唐振云[2] 

机构地区：[1]北京工业大学材料科学与工程学院,北京100124 [2]北京航空制造工程研究所高能束流加工技术重点实验室,北京100024

出　　处：《材料热处理学报》2010年第12期33-37,共5页Transactions of Materials and Heat Treatment

基　　金：国防预研支撑项目基金

摘　　要：焊前首先对TC4-DT钛合金母材进行不同固溶处理,进而研究电子束焊接对接头显微组织的影响。结果显示,在炉冷条件下960℃固溶处理的母材为双态组织,晶粒细小,焊缝轮廓清晰,热影响区为等轴初生α相和针状马氏体α′相,焊缝为"网篮状"马氏体组织;经1018℃固溶处理的母材为魏氏组织,晶粒粗大,焊缝轮廓模糊,热影响区为板条状α相和针状马氏体α′相,焊缝柱状晶宽度增加;经960℃+1018℃固溶处理的母材,魏氏组织晶粒尺寸最大,焊缝柱状晶宽度也最大。固溶后空冷处理的母材α片层厚度小,热影响区α相也小,但焊缝区的马氏体α′相变宽、变粗。A TC4-DT titanium alloy was first subjected to different solution treatment and then effect of electron beam welding on the microstructure of welded joint was investigated.The results show that a duplex structure of primary α-phase and β-phase transformed structure is formed in the alloy solution-treated at 960 ℃ under furnace cooling.The microstructure is fine and the weld contour is clear.The heat affected zone（HAZ） is composed of equiaxed primary α-phase and needle martensite α′ phase and basket-like martensite α′ phase is observed in the fusion zone（FZ）.After solution treatment at 1018 ℃,a coarse grained lamellar Widmanstatten microstructure forms and the HAZ consists of lath-like α-phase and needle martensite α′ phase.The width of FZ with column grains increases and the weld contour becomes unclear.For the alloy solution-treated at 960 ℃ ＋ 1018 ℃,the size of Widmanstatten microstructure is biggest and the width of FZ with column grains is widest.Under air cooling condition,the thickness of α lamellae both in base metal and HAZ is thinner than that at furnace cooling condition,however,the martensite α′ phase in FZ becomes thicker and wider.

关 键 词：热处理 TC4-DT钛合金 电子束焊接 显微组织 

分 类 号：TG456.3[金属学及工艺—焊接]