Engineers control microstructure of metallic 3D printed parts

Researchers at Oak Ridge National Laboratory have demonstrated an additive manufacturing method to control the structure and properties of metal components with greater precision than conventional manufacturing processes.

Ryan Dehoff, staff scientist and metal additive manufacturing lead at ORNL’s Manufacturing Demonstration Facility in Tennessee, presented the research this week at the Materials Science & Technology 2014 conference in Pittsburgh.

‘We can now control local material properties, which will change the future of how we engineer metallic components,’ Dehoff said in a statement. ‘This new manufacturing method takes us from reactive design to proactive design. 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.’

According to ORNL, the researchers demonstrated the method using an ARCAM electron beam melting system (EBM), in which successive layers of a metal powder are fused together by an electron beam into a three-dimensional product.

By manipulating the process to precisely manage the solidification on a microscopic scale, the researchers demonstrated three-dimensional control of the microstructure – or crystallographic texture – of a nickel-based part during formation.

Crystallographic texture plays an important role in determining a material’s physical and mechanical properties with applications from microelectronics to high-temperature jet engine components relying on tailoring of crystallographic texture to achieve desired performance characteristics.

‘We’re using well established metallurgical phenomena, but we’ve never been able to control the processes well enough to take advantage of them at this scale and at this level of detail,’ said Suresh Babu, the University of Tennessee-ORNL governor’s chair for Advanced Manufacturing. ‘As a result of our work, designers can now specify location specific crystal structure orientations in a part.’

Other contributors to the research are ORNL’s Mike Kirka and Hassina Bilheux, University of California Berkeley’s Anton Tremsin, and Texas A&M University’s William Sames.

The research was supported by the Advanced Manufacturing Office in the US Department of Energy’s Office of Energy Efficiency and Renewable Energy.