Aluminum nitride (AlN) ceramics and oxygen‐free Cu were brazed with multilayer filler consisted of Ag‐Cu‐Ti +Ni foam. The microstructure and forming principle of AlN/Cu joints were studied and the influence of Ni foam on the joints was focused. The result shows that the composition of AlN/Cu joint was AlN/TiN/Ni3Ti+Cu(s,s)+CuTi+Ni foam+Ag(s,s)/Cu. The joint strength was only 66.7 ± 3.7MPa with pure Ag‐Cu‐Ti solder and the fracture occurred inside AlN ceramics due to the residual stress. The foam nickel reacted with Ag‐Cu‐Ti filler metal to form Ni3Ti during brazing process. Ni foam still retained the basic skeleton structure during brazing, and the mechanical capacity of AlN/Cu joint was enhanced significantly. The maximum shear strength of the brazed joint can reach 89.6 ± 4.5 MPa with .1 mm Ni foam, and the fracture position changed to the brazing filler. The result shows that nickel foam can reduce the residual thermal stress, and the mechanical properties of AlN/Cu joints were improved.
The joining of AZ31B Mg alloy to Q235 steel was realized by metal inert-gas arc welding. Microstructure characteristics and tensile behaviors of Mg-steel joints with and without Cu addition were investigated and compared. Results show that the microstructure and tensile strength were improved with the addition of Cu interlayer. The IMC Mg 2 Cu with rod-like structure was generated in both the whole weld zone and Mg/steel interfacial zone. The maximum tensile strength of Cu-added joint can reach to 185 MPa, which partly fractured at the weld seam of Mg alloy instead of the Mg/Fe interface. The increase of the joint strength and microhardness profile with addition of Cu can be explained in terms of improvement of wettability of Mg alloy to steel and the formation of fine IMC Mg 2 Cu.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.