(1. 南京工程學(xué)院 材料工程學(xué)院，南京 211167；
2. 江蘇省先進(jìn)結(jié)構(gòu)材料與應(yīng)用技術(shù)重點(diǎn)實(shí)驗(yàn)室，南京 211167；
3. 南京航空航天大學(xué) 材料科學(xué)與技術(shù)學(xué)院，南京 211067)
摘 要: 采用NiCrMo-3焊絲實(shí)現(xiàn)純鎢(W)和0Cr13Al鋼的TIG熔釬焊接，利用OM、SEM、EDS、顯微硬度計(jì)和電子萬(wàn)能試驗(yàn)機(jī)等手段研究接頭的微觀(guān)組織、成分分布、力學(xué)性能及斷裂特征。結(jié)果表明：焊縫金屬與鎢母材形成的釬焊界面潤(rùn)濕性良好，鎢母材表面溶解后的W原子擴(kuò)散進(jìn)入焊縫金屬中，并在界面斷續(xù)形成厚度不超過(guò)1 μm的富W、Ni金屬間化合物層；焊縫金屬與鋼母材形成的熔焊界面主要因Ni元素的擴(kuò)散進(jìn)入，在鋼母材中沿熔合線(xiàn)形成寬5~10 μm的馬氏體層。焊縫金屬大致可分為W原子固溶強(qiáng)化區(qū)、完全混合區(qū)和不完全混合區(qū)等三個(gè)顯微硬度相差較大的區(qū)域。接頭抗拉強(qiáng)度為167 MPa，斷裂面主要位于距鎢母材/焊縫金屬結(jié)合面50~300 μm的鎢母材中，為典型的解理斷裂形貌。
關(guān)鍵字: 鎢；熔釬焊；解理斷裂
（1. School of Materials Engineering, Nanjing Institute of Technology, Nanjing 211167, China;
2. Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology, Nanjing 211167, China;
3. College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China）
Abstract:The dissimilar material joint between tungsten and 0Cr13Al steel was fabricated by TIG arc welding-brazing process with NiCrMo-3 wire as filling metal. The microstructures, composition distribution, fracture characteristics and properties of the joints were studied by OM, SEM, EDS, microhardness tester and electronic universal testing machine. The results show that NiCrMo-3 filler metal has a good wettability with tungsten. The W atoms from surface dissolution of tungsten diffuse into welding seam and the rich W, Ni intermetallic compound form on the interface of tungsten/welding seam which is discontinuous and the thickness is not more than 1 μm. The martensite layer whose thickness is 5-10 μm forms in steel along fusion line due to the diffusion of Ni element into steel. The welding seam can be roughly divided into W atom solid solution strengthening zone, complete mixing zone and incomplete mixing zone with great difference in microhardness. The tensile strength of joint is 167 MPa. Most of fracture surface is located in tungsten base metal and is 50-300 μm from the tungsten matrix/weld seam interface. The fracture is typical cleavage fracture.
Key words: tungsten; welding-brazing; cleavage fracture
