Advancing high-performance multi-material 3D printing
The new process, developed by Tohoku University researchers, was demonstrated during the creation of a lightweight yet durable automobile part
According to Tohoku University, researchers at the Institute for Materials Research and New Industry Creation Hatchery Center have made a breakthrough in a multi-material 3D printing technique – demonstrating the process for creating a lightweight yet durable automobile part.
“Multi-materials are a hot topic in the field of additive manufacturing due to its process flexibility,” said Associate Professor Kenta Yamanaka, from Tohoku University. “However, a major challenge in practical implementation is that for certain metal combinations, such as steel and aluminum, brittle intermetallic compounds can be formed at the dissimilar metal interfaces. So, while the material is now lighter, it ends up being more brittle.”
The goal of this study was to produce a steel-aluminum alloy that was lightweight but did not compromise on strength. To do so, the research team used Laser Powder Bed Fusion (LPBF). They discovered that increasing the scan speed of the laser significantly suppresses the formation of brittle intermetallic compounds (such as Al5Fe2 and Al13Fe4). They proposed that this higher scanning speed leads to something called non-equilibrium solidification, which minimizes solute partitioning that results in weak points in the material. The resulting product consequently demonstrated strong bonding interfaces.
“In other words, you can’t just slap two metals together and expect them to stick without a plan,” said Specially Appointed Assistant Professor Seungkyun Yim, from Tohoku University. “We had to fully understand the in-situ alloying mechanism first.”
Based on this achievement, the researchers successfully prototyped what they believe to be the world’s first full-scale automotive multi-material component (suspension tower) with a tailored geometry. The research group intends to apply these findings to other metal combinations where similar issues with bonding need improvement, which will allow for more broad applications.
The paper, titled ‘Multi-material additive manufacturing of steel/Al alloy by controlling the liquid/solid interface in laser beam powder bed fusion’ was published in Additive Manufacturing.
