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 µm and 340 nm to 42 µm, respectively.