SLAC Scientists use X-rays to observe metal parts by 3D

SLAC staff scientist Johanna Nelson Weker, front, leads a study on metal 3-D printing at SLAC’s Stanford Synchrotron Radiation Lightsource with researchers Andrew Kiss and Nick Calta, back. (Dawn Harmer/SLAC)

Scientists at the Department of Energy’s SLAC National Accelerator Laboratory are using X-ray light to observe and understand how the process of making metal parts using three-dimensional (3-D) printing can leave flaws in the finished product – and discover how those flaws can be prevented.

Metal 3-D printing is being developed for making highly specialized parts for the aerospace, aircraft, automotive and healthcare industries. Right now, companies like General Electric and Boeing that create metal parts with 3-D printing have to put each part and 3-D printer through vigorous qualification.

The scientists are using two X-ray methods to see what happens during metal 3-D printing. With one type of X-ray light, they create micron-resolution images as the layers of metal build up. The second one bounces X-rays off the atoms in the material to analyze its atomic structure as it changes from solid to liquid and back to solid form during the melting and cooling process.

They also plan to investigate another approach called “directed energy deposition”, in which, a laser beam hits and melts metal powder or wire, allowing creation of more complex geometric forms. This sort of 3-D printing is especially useful in making repairs.