“…Hence, this joint had the mechanically mixed (mechanical mixing) layers. Similar mechanically mixed layers were also observed in several dissimilar friction welded joints (Ruge, et al, 1986;American Welding Society, 1991;Yilmaz, et al, 1996;Fuwano, et al, 2000;Kim, et al, 2003;Straffelini, et al, 2004;Meshram, et al, 2007;Jayabharath, et al, 2007;Arivazhagan, et al, 2008;Ambroziak, 2010;Kimura, et al, 2011b) as well as that in the same combination of this study (Ando, et al, 1963;Aritoshi, et al, 1991;Ochi, et al, 2007). Furthermore, this joint had also the not-joined region at the adjacent region on the CP-Al side of the weld interface, which was indicated by arrows.…”