Behaviour of oxide at diffusion‐bonded interfaces in Al‐Mg‐Si series 6063 alloy: Study of diffusion‐bonding mechanism of aluminium alloys by transmission electron microscopy (1st Report)

Abstract

Summary The behaviour of the surface oxide film during the diffusion‐bonding of Al‐Mg‐Si series 6063 alloy and its influence on the bond strength have been investigated mainly by TEM observations in order to explain the effect of alloying elements on the bondability of aluminium alloys. When faying surfaces were finished by electro‐polishing, crystalline oxide particles smaller than a few 10‐1 μm in size were found to be dispersed on the joint interface of 6063 alloy, whereas a rather continuous film of amorphous oxide remained at the joint interface of commercially pure aluminium. When faying surfaces were finished by wire‐brushing, an interfacial zone of a few μ m thickness involving a number of fine oxide particles was found in the joint in 6063 alloy. A similar interfacial zone was also observed in a joint in pure aluminium, but its thickness and the density of oxide particles were much greater than those in the joint in 6063 alloy. The crystalline oxide particles at the joint interface of 6063 alloy ...