Identifying rhenium substitute candidate multiprincipal-element alloys from electronic structure and thermodynamic crite
- PDF / 981,063 Bytes
- 9 Pages / 584.957 x 782.986 pts Page_size
- 64 Downloads / 160 Views
FOCUS ISSUE
THERMODYNAMICS OF COMPLEX SOLIDS
Identifying rhenium substitute candidate multiprincipalelement alloys from electronic structure and thermodynamic criteria Axel van de Walle1,a)
, Julian E.C. Sabisch2, Andrew M. Minor3, Mark Asta4,b)
1
Box D, School of Engineering, Brown University, Providence, Rhode Island 02912, USA Energy Nanomaterials, Sandia National Laboratories, Livermore, California 94550, USA 3 Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA; and National Center for Electron Microscopy, Molecular Foundry Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA 4 Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA; and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA a) Address all correspondence to this author. e-mail: [email protected] b) This author was an editor of this journal during the review and decision stage. For the JMR policy on review and publication of manuscripts authored by editors, please refer to http://www.mrs.org/editor-manuscripts/. 2
Received: 5 April 2019; accepted: 2 May 2019
While rhenium has proven to be an ideal material in fast-cycling high-temperature applications such as rocket nozzles, its prohibitive cost limits its continued use and motivates a search for viable cost-effective substitutes. We show that a simple design principle that trades off average valence electron count and cost considerations proves helpful in identifying a promising pool of candidate substitute alloys: The Mo–Ru–Ta–W quaternary system. We demonstrate how this picture can be combined with a computational thermodynamic model of phase stability, based on high-throughput ab initio calculations, to further narrow down the search and deliver alloys that maintain rhenium’s desirable hcp crystal structure. This thermodynamic model is validated with comparisons to known binary phase diagram sections and corroborated by experimental synthesis and structural characterization demonstrating multiprinciple-element hcp solid-solution samples selected from a promising composition range.
Introduction Among the refractory metals, rhenium exhibits a unique combination of a high melting point, good ablation resistance, good high-temperature strength and creep resistance. Rhenium is known to be the only refractory element that does not display a measured ductile–brittle transition, such that it features relatively high ductility at low temperature [1, 2]. The combination of lowtemperature ductility and high melting point makes Re-based materials attractive as structural materials for applications such as rocket nozzles, which involve high temperatures and fast thermal cycling. However, the high cost (which have reached just over 10,000 $/kg in the past 15 years) and limited worldwide reserves of Re place a limit on its use [3, 4]. This situation has motivated the search for viable and cost-effective replacement strate
Data Loading...
