Vacuum diffusion bonding of surface textured stainless steel and aluminum

Using cold metal transfer (CMT) technology to achieve stainless steel surface texturing, a 3mm-high burr on the surface, whose distribution density is 9/cm², is obtained. Horizontal and vertical spacing of the burr centers are both 3 mm. vacuum diffusion bonding interface structure with aluminum under different holding time and studied changes in the organization and strength performance of the joint is analyzed. The results show that when the diffusion bonding temperature is 600 ℃, holding time is 60min, pressure is 3 MPa, the burrs penetrate inside the aluminum, which effectively remove the surface oxide film and help form a continuous joint Fe₂Al₅/FeAl₃ interface reaction layer. Compared to direct vacuum diffusion bonded stainless steel and aluminum, the tensile shear strength improved significantly. It found that when diffusion bonding temperature is constant, with increasing holding time, the reaction layer thickness increases. But when the holding time is too long, there is macroscopic deformation in the aluminum and therefore joint strength had a trend of first increasing and then decreasing with the increase of holding time.