D. Grundy, Jentek Sensors, Inc., Waltham, MA; V. Zilberstein, N. Goldfine, JENTEK Sensors, Inc., Waltham, MA; J. Green, I. Stol, ALCOA Technical Center, Pittsburgh, PA

Summary: Lack of Penetration (LOP) and kissing bonds (KB) are typical forms of discontinuities that may occur in friction stir welds (FSW). This paper will describe patented methods (U.S. patent # 6,727,691 and others pending) for the detection of these types of discontinuities. Results of a study demonstrating the capability of MWM-Array eddy current sensors to inspect and characterize FSWs in structural elements fabricated from aluminum alloy extrusions will be presented. MWM-Array generated images of electrical conductivity reveal microstructural variations on the backside of the FSW butt joints as well as discontinuities such as LOP and KB. The results will be compared with the data reported at the previous Trends in Welding Research Conference (2002).