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

Abstract

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.

GRAPHICAL ABSTRACT

KEYWORDS:

• Nanotwinned Al
• 9R phase
• stacking fault energy
• magnetron sputtering

Acknowledgements

This project is primarily funded by DoE-BES (Basic Energy Sciences) under grant number DE-SC0016337. The ASTAR crystal orientation system in TEM microscope is supported by ONR-DURIP award N00014-17-1-2921. Access to the Microscopy Facilities at Purdue University and Center for Integrated Nanotechnologies (managed by Los Alamos National Laboratory) are also acknowledged. Atomistic simulations were completed utilizing the Holland Computing Center of the University of Nebraska, which receives support from the Nebraska Research Initiative.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This project is primarily funded by DoE-BES (Basic Energy Sciences) [grant number DE-SC0016337]. The ASTAR crystal orientation system in TEM microscope is supported by ONR-DURIP award N00014-20-1-2659.