The effect of friction stir processing on the microstructure and mechanical properties of an aluminum lithium alloy

The article of record as published may be found at http://dx.doi.org/10.1007/s11661-008-9698-8Friction stir processing (FSP) was conducted on a wrought plate of AA2099 to refine and homogenize the microstructure and enhance the through-thickness ductility and fracture resistance. Optical microscopy (OM), orientation imaging microscopy (OIM), and transmission electron microscopy (TEM) methods were employed to evaluate microstructure and micro- texture in as-received material and in material subjected to FSP as well as postprocessing heat treatments. Hardness and orientation-dependent tensile test data were combined with anticlastic bending fatigue data to characterize the as-received, processed, and processed and heat-treated conditions of the material.Defense Advanced Research Projects Agency (DARPA)Office of Naval Research (ONR)Contract no. N00014-06-WR-2-0196 (ONR