Search

[Display omitted] • Cu-Nb composite diffused metal interlayer was first applied to TC4 and 4J36 electron beam welding. • The use of Cu-Nb interlayer produces solid solutions in the two weld melting zones. • The use of Cu-Nb interlayer improves the quality of welded joint between TC4 and 4J36. • The formation mechanism of 4J36/Cu-Nb/TC4 bonded joints was studied. Electron beam welding of 4J36 invar alloy and TC4 titanium alloy was carried out with Cu-Nb composite diffused metal interlayer. The results showed that the depth to width ratio and the tensile strength of welded joints increased with the increase of electron beam current. Under the designed process parameters, two melting zones (MZ) in welded joints formed solid solutions (ss), the welded joint tensile strength reached maximum value of 244.1 MPa, and the fracture location was mainly located at 4J36/Cu interface. [ABSTRACT FROM AUTHOR]

[Display omitted] • The cryogenic treatment was first applied to TC4/316L diffusion welded joint. • The effect of cryogenic treatment on microstructure of base metal TC4 and 316L was investigated. • The cryogenic treatment improves the quality of dissimilar joint between titanium alloy and stainless steel. • The bonding mechanism of joints and the influence mechanism of cryogenic treatment were analyzed. The diffusion welded joints of 316L/TC4 with Nb/Cu metal interlayer were subjected to cryogenic treatment. After cryogenic treatment, the strength of joints increased with the increase of soaking time. The strength of joints decreased with the increase of the cycle impact times. The average tensile strength of as-welded joints (AW) was 236.7 MPa, and the cryogenic treated samples for 24 h reached the best (280 MPa). The bonding mechanism of TC4/Nb/Cu/316L vacuum diffusion bonding joints and the influence mechanism of cryogenic treatment were analyzed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The deep cryogenic treatment was first applied to TC4/4J36 diffusion welding joint. • The effects of soaking time and cycles on mechanical properties of joint were studied. • The deep cryogenic treatment improves the quality of dissimilar joint between titanium alloy and steel. • The influence mechanism of deep cryogenic treatment on joint was studied. The diffusion welded joints of 4J36/TC4 with Ni/Cu/V metal interlayer were subjected to deep cryogenic treatment. The results showed that the extension of soaking time could improve the mechanical properties of the joint. The sample soaked for 8 h had the best performance, and it possessed ultimate tensile strength of 357.9 MPa and elongation of 24.9%. All samples failed at Cu/Ni interface with a ductile fracture manner, indicating that the joint still had good performance at low temperature. [ABSTRACT FROM AUTHOR]

• The V/Cu/Ni interlayer was first applied to weld TC4 titanium alloy and 4J36 invar alloy. • The use of V/Cu/Ni interlayer produces solid solutions at all interfaces. • The use of V/Cu/Ni interlayer improves the quality of dissimilar joint between titanium alloy and steel. • The formation mechanism of 4J36/Ni/Cu/V/TC4 bonded joints was studied. Diffusion bonding of 4J36 invar alloy and TC4 titanium alloy was carried out by inserting Ni/Cu/V multi-layer metal interlayer. The results showed that temperature had a significant effect on microstructure and mechanical properties of welded joints. At 890 °C, the joint tensile strength reached maximum value of 249.3 MPa. Fe-Ni solid solution ((Fe,Ni)ss), Cu-Ni solid solution ((Cu,Ni)ss), V-Cu solid solution ((V,Cu)ss) and Ti-V solid solution ((Ti,V)ss) were produced at interfaces of 4J36/Ni, Ni/Cu, Cu/V and V/TC4, respectively, and fracture surfaces of all joints showed dimples of different sizes, which showed that the application of Ni/Cu/V interlayer was an effective method. [ABSTRACT FROM AUTHOR]