Diffusion welding of Al-Sn alloy and steel in the atmosphere

Effects of single addition of Sn and combined addition of Sn and other element (Cu, Mg, Zn, Ti, Si, Bi, Cr, Mn or Ni) to aluminum on the diffusion weldability of steel and aluminum alloys in the atmosphere were investigated. Diffusion welding was mainly carried out at 873K for 3.6ks under pressure of 2MPa. After the welding, Fe2Al5 and FeAl3, whose total thickness range from about 30 to 100μm according to different alloying elements in aluminum, are produced in the diffusion layer. There is no correspondence between the fracture strength and the total thickness. The combined addition of Sn and Mg to aluminum produce the couple showing good weldability with the strength of about 50MPa, while the single addition of Sn shows the strength of only about 30MPa. All welding couples except Steel/Al-0.5Sn-1Cu, which fracture at initial welding interface, fracture at the position concentrated with Sn.