EVALUATION OF FRICTION WELD INTERFACE OF ALUMINUM TO AUSTENITIC STAINLESS-STEEL JOINT

A type 1050 commercial aluminium was bonded to a type 304 austenitic s tainless steel using a continuous drive friction welding process. The bonding interface conditions were evaluated by means of mechanical tes ts, to measure tensile and bending properties, and ultrasound microsco pic observation. The tensile strength of the joints increased as the f rictional rime increased. High strength joints could be obtained at a frictional time greater than 0.2 s. However, ultrasound microscopy cle arly showed that bonding progress occurred from the peripheral region towards the centre of the faying surface and, furthermore, that the fr ictional time of 0.2 s was not sufficient for complete bonding and muc h more frictional time was necessary. It is thus difficult to exactly evaluate the joint strength of a soft-hard metal combination by tensil e and bending tests alone. Therefore, ultrasound. (C) 1997 The Institu te of Materials.