MICROSTRUCTURE OF FRICTION WELD INTERFACE OF 1050-ALUMINUM TO AUSTENITIC STAINLESS-STEEL

Type 1050 aluminum was bonded to type 304 stainless steel by a frictio n welding procedure. The aluminium was greatly deformed, and the grain s were elongated and refined near the weld interface. The stainless st eel was slightly deformed and partly transformed at the faying surface from austenite to martensite owing to hard friction. As a result, the hardness of both materials in the vicinity of the weld interface was higher than that of the base metals. Constituent elements of both mate rials had interdiffused through the weld interface, and some intermeta llic compounds, Fe-2-Al-5, FeAl, and Fe3Al, were formed at the weld in terface. It was presumed by estimating with metallographic observation that the welding temperature was lower than the lowest eutectic tempe rature in the metal system. So the friction welding mechanism of this system was based on interdiffusion of each constituent in the solid st ate.