Australia's RMIT University Has Found That Ultrasound Can Enhance The Strength Of 3d-printed Alloys

Feb 26, 2020

RMIT university in Australia has found that the use of ultrasound in the 3D printing process can promote the metal alloy grains to be tighter, an advance that could lead to stronger and more consistent parts being printed. The microstructure of 3d-printed alloys is usually made up of large, thin crystals. These grains will cause low mechanical properties of 3d-printed alloys and increase the tendency of cracking during printing, thus limiting the practical engineering application of 3d-printed components.

At RMIT university in Melbourne, where ultrasonic waves are used in the printing process, the microstructure of the alloys looks remarkably different: the alloy crystals are very small and perfectly isoaxial, meaning they form equally in all directions across the printed metal parts.

RMIT university said tests showed that the tensile strength and yield stress of the parts increased by 12 per cent compared with conventional additive parts. The team demonstrated their ultrasonic method, which USES ti-6al-4v, a titanium alloy commonly used in aircraft parts and biomechanical implants, and Inconel 625, a nickel-based superalloy used in the offshore and petroleum industries.

By turning the ultrasonic generator on and off during the printing process, the team also showed how different microstructures and components could be used to make specific parts of a 3D printed object, which they thought would be useful for functional grading.

The researchers say the method is applicable not only to titanium and nickel-based superalloys, but also to other commercial metals such as stainless steel, aluminum and cobalt alloys. The technology is expected to scale up to achieve 3D printing of most industrially related metal alloys for use in higher performance structural parts or structural gradient alloys.