Effects of Mg and Sc additions on the microstructure and mechanical properties of Al–20Zn alloys

Abstract

The effects of Mg and Sc additions on the microstructures and mechanical properties of Al–20Zn alloys were studied. Results showed that the η and Zn phases precipitated in the Al–20Zn–Mg alloys during hot rolling and the size of the η phase increased with Mg content. The addition of Sc led to the formation of a high-density Al3Sc phase, which refined the Al grains and promoted the precipitation of the η and Zn phases in the Al–20Zn–Mg–Sc alloys during hot rolling. Mg and Sc additions led to η′ phase precipitation and grain boundary pinning in alloys with high Zn contents during solid solution treatment and aging. The mechanical properties of the Al–20Zn alloy with rolled and aged states improved after the simultaneous addition of 0.5 Mg and 0.5 Sc due to the increased precipitation and grain boundary strengthening effects and improved stress distribution during tension.