Researchers improve 3D printed alloys with ultrasound

Researchers at RMIT have found that sound vibrations can improve the micro-structure of 3D printed alloys.

The team used high frequency sound waves to make the alloys more consistent and stronger than those printed conventionally. Lead author, Carmelo Todaro, highlighted that the method deals with inconsistencies in 3D printed alloys.

“If you look at the microscopic structure of 3D printed alloys, they’re often made up of large and elongated crystals,” Todaro explained.

“This can make them less acceptable for engineering applications due to their lower mechanical performance and increased tendency to crack during printing.”

After the sound vibrations were applied during the printing process, testing showed a 12 per cent improvement in tensile strength and yield stress.

“The microscopic structure of the alloys we applied ultrasound to during printing looked markedly different: the alloy crystals were very fine and fully equiaxed, meaning they had formed equally in all directions throughout the entire printed metal part,” said Todaro.

The experiment tested commercially available alloys, including a titanium alloy and a nickel-based superalloy. The researchers also found that using their ultrasound technique could vary specific parts within a 3D printed object.

According to project supervisor, Ma Qian, the results demonstreated that the method could be applied widely.

“Although we used a titanium alloy and a nickel-based superalloy, we expect that the method can be applicable to other commercial metals, such as stainless steels, aluminium alloys and cobalt alloys,” Qian said.

“We anticipate this technique can be scaled up to enable 3D printing of most industrially relevant metal alloys for higher‑performance structural parts or structurally graded alloys.”