Phase stability and mechanical properties of novel high entropy transition metal carbides
| Autor: | Tyler Harrington, Cormac Toher, Pranab Sarker, Stefano Curtarolo, Lucas Borowski, Kevin Kaufmann, Patrick E. Hopkins, Cameron McElfresh, Donald W. Brenner, Christina M. Rost, Kenneth S. Vecchio, Jian Luo, Eduardo Marin, Olivia F. Dippo, Joshua Gild |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Polymers and Plastics High-entropy alloys Spark plasma sintering Thermodynamics 02 engineering and technology 01 natural sciences Carbide Transition metal Hardness 0103 physical sciences Ceramic Ball mill Materials 010302 applied physics High entropy alloys Mechanical Engineering Metals and Alloys Multicomponent Materials Engineering Nanoindentation 021001 nanoscience & nanotechnology Condensed Matter Physics Electronic Optical and Magnetic Materials visual_art Ceramics and Composites visual_art.visual_art_medium Carbides 0210 nano-technology Solid solution Entropy-stabilized |
| Popis: | Twelve different equiatomic five-metal carbides of group IVB, VB, and VIB refractory transition metals are synthesized via high-energy ball milling and spark plasma sintering. Implementation of a newly developed ab initio entropy descriptor aids in selection of candidate compositions for synthesis of high entropy and entropy stabilized carbides. Phase formation and composition uniformity are analyzed via XRD, EDS, S/TEM-EDS, and EXAFS. Nine of the twelve candidates form true single-phase materials with the rocksalt (B1) structure when sintered at 2473 K and can therefore be investigated as high entropy carbides (HECs). The composition (V0.2Nb0.2Ta0.2Mo0.2W0.2)C is presented as a likely candidate for further investigation as an entropy stabilized carbide. Seven of the carbides are examined for mechanical properties via nanoindentation. The HECs show significantly enhanced hardness when compared to a rule of mixtures average of the constituent binary carbides and to the highest hardness of the binary constituents. The mechanical properties are correlated to the electronic structure of the solid solutions, offering a future route to tunability of the mechanical properties of carbide ceramics via exploration of a new complex composition space. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|