Effect of Alloying Element on Behavior of Oxide Film at Diffusion-welded Interface of Aluminum Alloys

Study on Surface Film at Diffusion-welded Interface (Report 4)

Abstract

It is not easy to obtain the sound diffusion-welded joints of aluminum, because the oxide film on diffusion-welded interface does not disappear during welding. To improve the mechanical properties of the diffusion-welded joints of aluminum, the relations between alloynig elements and the behavior of oxide film at diffusion-welded interface of aluminum alloys were investigated with a tensile test, Auger electron spectroscopy, X-ray photospectroscopy and electron probe microanalyzer. Materials used were pure Al, A1070, A2014, A3003, A4032, A5083, A6N01, A7003 and Al-2.5Li alloy.
The welding surface films of aluminum alloys used consisted of the alumina. Mg oxide and Li oxide were more detected with the increase in the content of Mg and Li in the aluminum alloys. The alumina film on the welded surface of the the aluminum alloys reacted with the alloying element Mg during diffusion welding and changed to MgAl₂O₄. On the intimate contact zone, the reaction formed the metallic bonding, when aluminum alloys contained 0.1-2 mass%Mg. The joints of A6N01 and A3003 alloy were most soundest in the aluminum alloys tested.