By Mark Norfolk on Tuesday, August 25th, 2020
Due to their unique microstructure, amorphous metals combine ultrahigh strength with high hardness and can sustain larger reversible deformations than crystalline alloys in one single material. Amorphous metals are more corrosion resistant compared to conventional metals due to their lack of long-range periodicity, related grain boundaries and crystal defects such as dislocations.
However, amorphous materials are often not considered in engineering applications due to the difficulty in joining them to other materials and limitations in manufacturing thick sections.
Recently Fabrisonic, and other team members, worked to overcome these limitations by using Ultrasonic Additive Manufacturing (UAM). UAM uses ultrasonic energy to produce metallurgical bonds between layers of metal foils near room temperature. This low-temperature attribute of the process enables the joining of dissimilar metal alloys with little to no intermetallic formation while simultaneously maintaining the original foil microstructure.
UAM allows the processing of amorphous alloys to useful size without destroying their beneficial properties. Conventionally, amorphous alloys are limited to less than 1 mm in thickness. UAM technology remedies this limitation. In this study, amorphous alloy foils were joined to themselves and onto crystalline substrates of interest for cladding applications.
These joints were found to be strong while having minimal changes to the joint, substrate, and foil microstructure. These cladded surfaces may find use in high wear or corrosive environments for space and earth-based applications due to their superior properties over crystalline metals.
The authors would like to acknowledge financial support from NASA’s SBIR Office, contract 80NSSC19C0589.