Complex interactions between precipitation, grain growth and recrystallization in a severely deformed Al-Zn-Mg-Cu alloy and consequences on the mechanical behavior

Combining submicrometer grain size with nanoscaled precipitation is an attractive approach to achieve high yield stress reasonable ductility in aluminum alloys. The control of super saturated solid solutions decomposition ultrafine structure during annealing treatments however a huge challenge. It raises indeed the general question competition between precipitation, growth and recrystallization. All these microstructure changes are driven by minimization free energy system but connected three different factors, thermodynamic driving force, boundary dislocation density, respectively. In this work, we have systematically investigated interconnection mechanisms Al-Zn-Mg-Cu alloy processed pressure torsion at room temperature from solutionized state. Ageing heat were carried out study kinetics using complementary characterization techniques such as in-situ small-angle X-ray scattering, differential scanning calorimetry, transmission electron microscopy atom probe tomography. Experimental data clearly demonstrate that starts much lower deformed state sequence modified compared classical coarse alloy. Beyond detailed understanding recrystallization recovery processes, systematic relationship microstructural features mechanical behavior was also studied. A special emphasis given on specific contribution precipitates nucleated heterogeneously along boundaries.