Microstructural evolution of nanotwinned Al-Zr alloy with significant 9R phase

Aluminum (Al) alloys have a multitude of applications, notably in the automotive, aerospace and coating industries, yet they exhibit significantly lower mechanical strength than conventional steels. Nanotwins drastically improve mechanical strength while retaining ductility. However, the high SFE of Al largely prevents twinning. Here, we synthesize Al-Zr alloy films containing an abundance of incoherent twin boundaries and 9R phases. These alloys exhibit an extended solid solubility of Zr, retaining a columnar nanotwinned structure across all compositions. These films reach a hardness up to 4.2 GPa with 10 at% Zr and demonstrate the capacity for producing strong Al alloys with nanotwins.

Automated summary

Aluminum (Al) alloys are widely used in various industries, but have lower mechanical strength compared to conventional steels. Adding Zr elements can significantly improve the mechanical properties of Al alloys, making them harder and more ductile. By synthesizing Al-Zr alloy films with a nanotwinned structure, it is possible to produce strong Al alloys with enhanced mechanical properties.