Effect of interlayer addition on microstructure and mechanical properties of NiTi/stainless steel joint by electron beam welding
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2021年第2期
论文作者：H.Niu H.C.Jiang M.J.Zhao L.J.Rong
文章页码：16 - 24
摘 要：Ni Ti/Stainless Steel（SS） sheets have been welded via a vacuum electron beam welding process, with three methods（offsetting electron beam to SS side without interlayer, adding Ni interlayer and adding Fe Ni interlayer）, to promote mechanical properties of the Ni Ti/SS joints. The joints with different interlayers are all fractured in the weld zone near the Ni Ti side, which is attributed to the enrichment of intermetallic compounds including Fe2 Ti and Ni3 Ti. The fracture mechanisms of different joints are strongly dependent on the types of interlayers, and the joints without interlayer, adding Ni interlayer and adding Fe Ni interlayer exhibit cleavage fracture, intergranular fracture and mixed fracture composed of cleavage and tearing ridge, respectively. Compared with the brittle laves phase Fe2 Ti, Ni3 Ti phase can exhibit certain plasticity, block the crack propagation and change the direction of crack propagation. The composite structure of Ni3 Ti and Fe2 Ti will be formed when the Fe Ni alloy is taken as the interlayer, which provides the joint excellent mechanical properties, with rupture strength of 343 MPa.
H.Niu1,2，H.C.Jiang1，M.J.Zhao1，L.J.Rong1
1. CAS Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Science2. School of Materials Science and Engineering, University of Science and Technology of China
摘 要：Ni Ti/Stainless Steel（SS） sheets have been welded via a vacuum electron beam welding process, with three methods（offsetting electron beam to SS side without interlayer, adding Ni interlayer and adding Fe Ni interlayer）, to promote mechanical properties of the Ni Ti/SS joints. The joints with different interlayers are all fractured in the weld zone near the Ni Ti side, which is attributed to the enrichment of intermetallic compounds including Fe2 Ti and Ni3 Ti. The fracture mechanisms of different joints are strongly dependent on the types of interlayers, and the joints without interlayer, adding Ni interlayer and adding Fe Ni interlayer exhibit cleavage fracture, intergranular fracture and mixed fracture composed of cleavage and tearing ridge, respectively. Compared with the brittle laves phase Fe2 Ti, Ni3 Ti phase can exhibit certain plasticity, block the crack propagation and change the direction of crack propagation. The composite structure of Ni3 Ti and Fe2 Ti will be formed when the Fe Ni alloy is taken as the interlayer, which provides the joint excellent mechanical properties, with rupture strength of 343 MPa.
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