Researchers from Pennsylvania State University, based in University Park, Pennsylvania, USA, have used a new Additive Manufacturing method to produce a complex metal build fusing two metals together into a single structure, a process that was once only possible with welding.
Using multi-material Laser Beam Powder Bed Fusion (PBF-LB) and a newly acquired machine at Penn State’s Center for Innovative Materials Processing Through Direct Digital Deposition (CIMP-3D), the researchers manufactured a complex structure out of a blend of low-carbon stainless steel and bronze, which consists of 90% copper and 10% tin.
“In a process called selective powder deposition, we can now melt multiple powdered metals in a single layer during the Additive Manufacturing process — and we were the first university in the US to do so,” said Jacklyn Griffis, a doctoral candidate in mechanical engineering and first author of the paper. “The fine powders are tens of microns in diameter, almost like flour. We can selectively deposit the powder with micron-level resolution, then melt it together with a laser.”
The researchers used an Aerosint selective powder deposition machine integrated into an existing 3D Systems ProX320 AM machine in the Systems for Hybrid-Additive Process Engineering (SHAPE) Lab at CIMP-3D. Griffis explained that a one-centimetre-tall metal part includes thousands of layers of metal powder and takes a few hours to build.
“We now have the processing technology to print these multi-material metal parts, as well as a way to monitor the melt pool and observe and address potential issues in real time,” said corresponding author Guha Manogharan, associate professor of mechanical engineering, head of the SHAPE Lab and co-director of CIMP-3D. “To do this, we produce a digital 3D rendering of the part through CT scans, which we use to look for pores, cracks at the interface or micron-scale defects.”
Pour lire l'article complet : Penn State researchers achieve breakthrough in multi-metal AM
