Nanoscale Analysis of Solute Distribution in Ultrahigh-Strength Aluminum Alloys

Nanoscale microstructural analysis and evaluation of mechanical properties were conducted on severely cold-rolled aluminum alloys. In order to examine the effect of alloying elements on microstructure and mechanical properties, Al–Cu–Mg, Al–Mg–Si and Al–Zn–Mg–Cu alloy sheets were prepared for systematic investigation. The SAXS and SANS were used to analyze the nanoscale microstructures in solution-treated and rolled samples of Al–Cu–Mg and Al–Zn–Mg–Cu alloys, and the results quantitatively revealed that nanoscale clusters are formed regardless of with or without rolling. HR-TEM, HAADF-STEM, thermal analysis, hardness and electrical conductivity measurements also suggested that the clusters are formed in cold-rolled samples. Mechanical property evaluations showed that strength generally increased, and ductility decreased with increasing cold-rolling reduction. The strength tended to increase with increasing solute content regardless of the alloy system.