Leveraging Quasicrystals in Additive Manufacturing: Structure, Properties, and Potential

Speaker

Dr. Andrew D. Iams, materials research engineer at the National Institute of Standards and Technology (NIST), Material Science and Engineering Division.

Abstract

Quasicrystals, first discovered at National Institute of Standards and Technology (NIST) in the early 1980s, have structures with long-range order without periodicity, giving rise to unique mechanical and physical properties. However, their broader application has been limited since most compositions require rapid solidification for their formation. Metal-based additive manufacturing offers a promising new pathway, as its high thermal gradients and rapid solidification conditions can promote quasicrystal formation.

In this presentation, I will discuss recent work at NIST revisiting the quasicrystal through metal-based additive manufacturing. I will begin with background on quasicrystals, including their original discovery at NIST, and introduce the unique processing environment of laser powder bed fusion. Specifically, I will present results on a high-strength Al-Zn-Mg-Cu alloy (AA7A77) fabricated using additive manufacturing. Multi-scale characterization revealed a bimodal microstructure, with fine equiaxed grains containing metastable Al₃Zr precipitates and coarse grains enriched with a previously unreported Mg₃₂(Al,Zn,Cu)₄₉ icosahedral quasicrystal. Transmission electron microscopy confirmed fivefold, threefold, and twofold symmetries, verifying the icosahedral structure. Thermodynamic modeling indicated that this quasicrystal forms near the end of solidification, while nanoindentation measurements showed hardness comparable to peak-aged AA7075. These results demonstrate how quasicrystals and dislocation networks can contribute to strengthening, highlighting new opportunities for leveraging aperiodic order in advanced structural alloys.

These findings highlight the potential to intentionally incorporate quasicrystals into lightweight alloys via additive manufacturing and present new strategies for designing high-performance structural materials.

Biography

Andrew D. Iams is a materials research engineer at the National Institute of Standards and Technology (NIST) in the Material Science and Engineering Division. Prior to NIST, Andrew was a senior engineer at the Westinghouse Electric Company – Material Center of Excellence, where he led various materials and manufacturing projects for the commercial nuclear industry. He received his Ph.D. in Material Science and Engineering from the Pennsylvania State University.