Metal components can now be printed in 3D with higher precision than ever before, thanks to US researchers. The control over the metal’s structure and properties that has been achieved is unmatched by conventional manufacturing processes.
3D printing is predicted to revolutionize manufacturing because it enables the precise fabrication of individualized, custom-made products at low cost. Materials such as metals, food, plastics, ceramics and even human tissue are starting to be printed this way. 3D printed metallic products are finding use in the aerospace, motorsport and energy industries, in biomedical devices and implants, and in robotics.
Ryan Dehoff from the Oak Ridge National Laboratory, US, and colleagues, have been working to improve the manufacture of components printed from Inconel 718, an austenitic nickel-chromium-based superalloy with a complex microstructure. This alloy is traditionally used in aircraft engines, gas turbines, energy systems and other high temperature applications.
The team were working with a commercially available electron beam melting machine that uses an electron beam to fuse together successive layers of metal powder into a 3D product. By controlling the heating parameters during the printing process the team found they could control the solidification process on the millimeter scale across the entire 3D product. This in turn meant the orientation of the metallic grains, the material’s microstructure, could be controlled very precisely across the entire component. This is significant because a material’s microstructure plays an important role in determining it physical and mechanical properties.
Dehoff’s team demonstrated that the temperatures used, the temperature gradient applied to the alloy, and the speed of solidification were all instrumental to determining the microstructure of the final product. And tweaking these parameters allowed the researchers to fabricate microstructures with a level of detail and control not possible using conventional manufacturing processes.
The researchers describe their work at potentially the most important development in metal 3D printing since its conception.
“We can now control local material properties, which will change the future of how we engineer metallic components,” Dehoff said. “It will help us make parts that are stronger, lighter and function better for more energy-efficient transportation and energy production applications such as cars and wind turbines.”