|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||High Entropy Alloys V
||L-108: Synthesis of High-entropy Metal Diborides and Fluorite Oxides
||Joshua Gild, Yuanyao Zhang, Tyler Harrington, Kenneth Vecchio, Jian Luo
|On-Site Speaker (Planned)
Several equimolar, five-component, metal diborides were fabricated via high-energy ball milling and spark plasma sintering. The majority of them possess virtually one solid-solution boride phase of hexagonal AlB2 structure, while a few of compositions also have minor secondary boride phases. Revised Hume-Rothery size-difference factors are proposed and used to rationalize the formation of high-entropy solid solutions in metal diborides. Greater than 92% of the theoretical densities have been generally achieved with largely uniform compositions (albeit some Nb clustering in selected specimens) with simple spark plasma sintering at 2000 ˚C for 5 minutes. Further studies have been conducted to use sintering aids to improve the densities and prolonged annealing at high temperature to further homogenize the specimens. More recently, high-entropy oxides of the cubic fluorite structure have also been synthesized and characterized. These materials represent new classes of ultra-high temperature ceramics as well as new types of high-entropy materials.
||Planned: Supplemental Proceedings volume