They developed dual-phase crystal plasticity computational models to understand the mechanistic roles played by both the FCC and BCC nanolamellae, and how they work together to give the material added strength and ductility. Zhu’s group at Georgia Tech led the computational modeling for the research. “The ability to produce strong and ductile HEAs means that these 3D-printed materials are more robust in resisting applied deformation, which is important for lightweight structural design for enhanced mechanical efficiency and energy saving,” says Jie Ren, Chen’s PhD student and first author of the paper. Our findings are original and exciting for materials science and engineering alike.” For many applications, a combination of strength and ductility is key. Compared to conventional metal casting, “we got almost triple the strength and not only didn’t lose ductility, but actually increased it simultaneously. “This unusual microstructure’s atomic rearrangement gives rise to ultrahigh strength as well as enhanced ductility, which is uncommon, because usually strong materials tend to be brittle,” Chen says. The hierarchical nanostructured HEA allows co-operative deformation of the two phases. This microstructure looks like a net, and is made of alternating layers known as face-centered cubic (FCC) and body-centered cubic (BCC) nanolamellar structures embedded in microscale eutectic colonies with random orientations. Because the process causes materials to melt and solidify very rapidly, compared with traditional metallurgy, “you get a very different microstructure that is far-from-equilibrium” in the components created, Chen says. However, “the potential of harnessing the combined benefits of additive manufacturing and HEAs for achieving novel properties remains largely unexplored,” says Zhu.Ĭhen and his team in the Multiscale Materials and Manufacturing Laboratory combined an HEA with a state-of-the-art 3D printing technique called laser powder bed fusion to develop new materials with unprecedented properties. Laser-based 3D printing can produce large temperature gradients and high cooling rates that are not readily accessible by conventional routes. Traditional alloys, such as brass, carbon steel, stainless steel and bronze, contain a primary element combined with one or more trace elements.Īdditive manufacturing, also called 3D printing, has recently emerged as a powerful approach to material development.

Comprised of five or more elements in near-equal proportions, they offer the ability to create a near-infinite number of unique combinations for alloy design. Over the past 15 years, high-entropy alloys (HEAs) have become increasingly popular as a new paradigm in materials science. The work, led by Wen Chen, assistant professor of mechanical and industrial engineering at UMass Amherst, and Ting Zhu, professor of mechanical engineering at Georgia Tech, is reported in a paper in Nature.

This alloy could be used to produce higher-performance components for applications in aerospace, medicine, energy and transportation. Image: UMass Amherst.Ī team of researchers at the University of Massachusetts (Umass) Amherst and the Georgia Institute of Technology has 3D-printed a dual-phase, nanostructured high-entropy alloy that exceeds the strength and ductility of other state-of-the-art additively manufactured materials. Wen Chen stands in front of images of 3D-printed high-entropy alloy components (heatsink fan and octect lattice, left) and a cross-sectional electron backscatter diffraction inverse-pole figure map demonstrating a randomly oriented nanolamella microstructure (right).

High entropy alloys