The 319th Forum: Combinatorial Strategies to Develop and Understand Metallic Glasses
Jan Schroers is a professor in the Department of Mechanical Engineering and Materials Science at Yale University. He received his Ph.D. in Physics from the RWTH Aachen. He spent three years at Caltech as a post-doc before joining Liquidmetal Technologies from 2002 to 2006 as a Director of Research where he developed processing methods for bulk metallic glasses. He recently co-founded Supercool Metals. His research focuses on combinatorial material science, metallic glasses, foams and composites, high-entropy alloys, nano and micro fabrication techniques, nucleation and solidification phenomena, and artificial microstructures as models to investigate microstructure-property relations. His research has resulted in over 140 journal publications and 23 patents and patent applications.
The increasing demands on materials across fields poses a grand challenge and requires the development and therefore understanding of increasingly more complex materials. Such complexity involves the materials’ chemistry, structure, and often material-specific processing methods.
In this talk, I want to focus on materials’ chemistry. For this, we will use combinatorial sputtering to fabricate large numbers of alloys simultaneously and subsequently use high-throughput methods to characterize the various alloys effectively. For most material classes, thin film effects and, more generally, fabrication specific effects, can dramatically affect structure and characteristic of the material. For metallic glasses, and that is one reason we focus on them here in this talk, this effect is much less pronounced and for some characteristics absent.
We will argue that the most effective strategy for the development of metallic glasses is a combination of theory, combinatorial approaches, and followed by precise traditional characterization. The multicomponent nature of bulk metallic glasses imposes a challenge for their discovery process. Rough estimations suggest that only a minute fraction of potential compositional space for bulk metallic glass formers has been explored thus far.
Here we introduce combinatorial strategies to fabricate libraries comprising of ~1000 different compositions. We use magnetron co-sputtering from three elemental targets that are oriented to create compositional gradients. The resulting composition library is explored for promising compositions. We use a massively parallel characterization method to determine the solidification temperatures, which we correlate with glass forming ability. Also in a massively parallel fashion, we determine the thermoplastic forming ability, which reflects in addition to the glass forming ability, the BMG’s ability for plastic-like processing. Both methods are effective in navigating through the vast composition space towards glass forming compositions. The vast amounts of data are stored, managed, and shared through an online data repository, which will be introduced.
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