Solute Distribution and Mechanical Properties of Ultra‐Fine‐Grained Al‐Mg Alloys

Ultra-fine-grained (d similar to 200 nm) Al-Mg alloys exhibit outstanding strength due to both Hall-Petch grain-size strengthening and solid-solution strengthening. When the solubility limit is exceeded, some Mg segregates to grain boundaries. This impacts both thermal stability and mechanical properties. In this study, alloys with between 0 wt.% Mg (pure Al) and 10.5 wt.% Mg are made by ball milling powders in liquid nitrogen, and consolidated by hot isostatic pressing and extrusion. The alloys are exposed to temperatures up to 500 deg. C. Microhardness and tensile behavior are measured and correlated with the microstructure, as measured by local-electrode atom-probe tomography, X-ray diffraction, and electron microscopy.