Researchers “Program” Structural Properties into 3D-Printed Metals

Metal 3D printing, or additive manufacturing, has enabled the production of parts with complex geometries that were once impossible to construct. However, the technique comes with a drawback: it may result in metals with reduced performance.

For thousands of years, metal manufacturing has relied on a process of “heating and beating” to shape the material and influence its mechanical properties. For instance, hot forging steel reduces ductility and improves strength. But the intricate shapes of 3D-printed metal parts prevent them from undergoing a similar beating process, limiting the customization of properties and performance.

Now, scientists at the Univ. of Cambridge have designed a novel 3D printing strategy that circumvents the need to “heat and beat” metal. The key innovation lies in the ability to program how a metal’s internal structure will formulate during the layer-by-layer printing process.

“Everybody is crazy about additive manufacturing because you can make complex shapes,” says study lead author Matteo Seita, a Granta Design Assistant Professor in Cambridge’s Dept. of Engineering, “but what really interests me is the internal structure of the metal. Depending on the size, shape, and some other characteristics of these crystals, the material can have very different mechanical properties.”

Whether a metal is soft or hard depends in part on tiny defects in the atomic structure, known as dislocations. In...