3D-printed space metal ready for tensile testing
This February, the first-ever metal part 3D-printed in space landed on Earth. Produced in the European Space Agency’s Metal 3D Printer Technology Demonstrator on the International Space Station (ISS), it is now in the hands of ESA’s engineers at ESTEC, the agency’s technical centre in the Netherlands, who poke and prod it to understand how microgravity affected its printing process.
“We are comparing this metal part with an identically shaped one created here on Earth, using the same printer before it was shipped to the ISS,” explains Caterina Iantaffi, ESA’s materials engineer. “What we are looking for are differences attributable to different gravity levels.”
After a visual inspection using a microscope and a CT scan, the parts were cut into their final shape. In a process called machining, the individual parts that make up the full metal sample – three larger dog-bone-shaped ones and three smaller cylindrical ones – were separated from the base, and their 'skin' was removed, leaving them with a very smooth surface.
Each of the three larger samples was sprayed with paint to create a fine randomised speckle pattern on its surface. This pattern was scanned as the testing machine gripped each end of the sample and pulled until it snapped.
Caterina explains: “As the sample was being stretched, the speckle pattern deformed accordingly, allowing us to assess the strain of the material. The three smaller cylinders were tested in a similar way, but by bending instead of stretching.”
[Image description: This photo shows a laboratory environment illuminated with intense blue lighting. A person wearing a blue lab coat with a small logo of the European Space Agency is working with a precision instrument. The setup includes a metallic device with a central clamp holding a thin rod sample, which the person’s gloved hand is carefully adjusting.]
