Researchers at NASA's Jet Propulsion Laboratory are implementing a printing process that transitions from one metal or alloy to another in a single object. JPL scientists have been developing a technique to address this problem since 2010. An effort to improve the methods of combining parts made of different materials in NASA's Mars Science Laboratory mission inspired a project to 3D print components with multiple alloy compositions.

Scientists make a rocket nozzle using a new 3D printing technique that allows for multiple metallic properties in the same object. (NASA-JPL/Caltech)

"We're taking a standard 3D printing process and combining the ability to change the metal powder that the part is being built with on the fly," said Douglas Hofmann, a researcher in material science and metallurgy at JPL, and visiting associate at Caltech. "You can constantly be changing the composition of the material."

In their new technique, Hofmann and his colleagues deposit layers of metal on a rotating rod, thus transitioning metals from the inside out, rather than adding layers from bottom to top, as in the more traditional 3D printing technique. A laser melts metal powder to create the layers.