Influences of metastable θ″, θ′ and stable θ intermetallics formed during cryorolling and friction stir welding process on AA2219

This paper presents a detailed investigation on the formation of θ′ and θ″ precipitates in the Cryorolled (CR) material of AA2219 alloy and the Friction Stir (FS) welded portion of CR AA2219 and their influence on material characterizations. The ultrafine grain formation and precipitate dissolutions in CR AA2219 and FS weld were characterized using optical, Scanning Electron (SEM) and Transmission Electron Microscopes (TEM). X-Ray Diffraction (XRD) was carried out to distinguish the phase changes of base AA2219, CR AA2219 and FS weld portion.