Abstract
Al 7075 alloys are used extensively in aircraft and aerospace structures due to their high strength-to-density ratio as well as moderate toughness and corrosion resistance. It has been commonly accepted that a sequence of precipitation reactions occur in conventional Al 7075 with increasing temperature: solid solution->Guinier-Preston (G-P) zones-> eta '-> eta . The formation and dissolution of the precipitates have a significant influence on the mechanical behavior of the materials. In this paper, gas atomized Al 7075 powder was modified by using the cryomilling technique to develop an ultrafine grain microstructure. The cryomilled material is compared to conventional material by investigating the morphology and microstructure of the powders, the precipitation reactions, and the mechanical behavior and microstructure evolution in bulk consolidated materials.