Researchers at Carnegie Mellon address the need for new 3D printing materials

As additive manufacturing expands with more industry and real-world applications, the need for new materials also grows. However, materials tend to remain conventional, limiting the technologies’ capabilities.

Currently-used materials, such as the common titanium alloy Ti-6Al-4V, were designed and optimized decades ago for traditional manufacturing approaches. Today, manufacturers are pushing for the creation of new materials, so that they can use metal powders designed for 3D printing and its high cooling rates.

However, designing new allows can be time consuming and require massive investment.

“It’s very hard to develop new materials for additive manufacturing, because evaluating new alloys requires a lot of powder. At least a hundred pounds of powder would be needed per composition in order to test all the process variables related to that material. This is both expensive and time-consuming,” explains Bryan Webler, assistant professor of materials science and engineering. “Even at a research scale, it’s not straightforward or efficient to fabricate small batches of powder for every possible material composition that we need to test.”

He explains that they would need computational and experimental approaches to screen compositions to provide some initial guidance before they can try to make test batches of powders.

For this reason, the researchers have designed a rapid screening method for new 3D printing alloys. The method allows users to quickly understand and develop correlations between process variables and alloy composition.

Scanning electron microscope images showing how an additive manufacturing laser pass refines the microstructure of a titanium boron (Ti-B) alloy. The image on the left is titanium boron before the laser pass and the image on the right is after the laser pass. (Photo: Carnegie Mellon)

The team addresses the experimental approach to composition screening by using solid material instead of powder. Using an arc-melting process, Webler can produce small metal buttons of virtually any composition. Up to 16 of these buttons can be placed in a 3D printing machine to make tracks and pads of remelted material on each button over a range of process variables including beam power and travel speed. After characterizing the melt pools, initial insights can be gained into how that alloy reacts to the fast solidification rates of 3D printing.

engineering.cmu.edu