Achieving Superior Strength and Ductility Combination Through Cryorolling in 2219 Aluminum Alloy

In aluminum 2219 alloy, a combination of ultra-fine grains and coarse grains was established through cryorolling. Formation of bimodal grain distribution was confirmed using electron backscattered diffraction analysis, transmission electron microscopy and x-ray diffraction analysis. Cryorolled samples showed a 3% increase in strength, with a 4% increase in ductility. An increase in dislocation density, reduced slip distance and bimodal grain structure were attributed to the strength-ductility combination. Dislocation annihilation rate and driving force for dislocation movement were also determined based on the temperature of deformation and dislocation density in rolled material. The unidirectional and cross-directional cryorolled samples resulted in a grain size ranging from 510 nm to 73 mu m and 340 nm to 42 mu m, respectively.