High‐Strength Nanotwinned Al Alloys with 9R Phase
Abstract
Light‐weight aluminum (Al) alloys have widespread applications. However, most Al alloys have inherently low mechanical strength. Nanotwins can induce high strength and ductility in metallic materials. Yet, introducing high‐density growth twins into Al remains difficult due to its ultrahigh stacking‐fault energy. In this study, it is shown that incorporating merely several atomic percent of Fe solutes into Al enables the formation of nanotwinned (nt) columnar grains with high‐density 9R phase in Al(Fe) solid solutions. The nt Al–Fe alloy coatings reach a maximum hardness of ≈5.5 GPa, one of the strongest binary Al alloys ever created. In situ uniaxial compressions show that the nt Al–Fe alloys populated with 9R phase have flow stress exceeding 1.5 GPa, comparable to high‐strength steels. Molecular dynamics simulations reveal that high strength and hardening ability of Al–Fe alloys arise mainly from the high‐density 9R phase and nanoscale grain sizes.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 22, 2018
- Source ID
- 10.1002/adma.201704629
Entities
People
- Adenike Giwa
- Anthony H. Kwong
- Haiyan Wang
- Han Wang
- Jian Wang
- Jie Ding
- Julia R. Greer
- Qiang Li
- Shuai Shao
- Sichuang Xue
- Xinghang Zhang
- Yue Liu
- Zhe Fan
- Zhimin Qi
Organizations
- California Institute of Technology
- Louisiana State University
- Oak Ridge National Laboratory
- Office of Naval Research
- Purdue University
- Shanghai Jiao Tong University
- United States Department of Energy
- University of Nebraska–Lincoln