Diffusion bonding of aluminum alloy, 8090

The ability to diffusion bond superplastic aluminum alloys would greatly enhance superplastic forming technology (SPF). The main obstacle to diffusion bonding Al alloys is the tenacity of the oxide layer. Vapor deposited interlayers to allow transient liquid phase bonding would be one method to overcome this problem. This study describes the effect of the surface chemistry of Al alloy 8090 (2.4Li-1.18Cu-0.57Mg-0.14Zr-Al) on the integrity of the diffusion bonds produced with both bare surfaces and an interlayer of Cu or Zn. With all other things equal, the Cu interlayer resulted in stronger diffusion bonds than the Zn interlayer or bare surfaces. Also, although Zn should allow for the use of lower temperature transient liquid phase bonding no structural advantage was seen.