From nano-structure to laves phase: Reduced thermal conductivity from medium-entropy alnbv to high-entropy alnbvcrti alloys
Journal
Materialia
Journal Volume
14
Start Page
100889
ISSN
25891529
Date Issued
2020
Author(s)
Jhong, Meng-Jie
Jen, I-Lun
Wang, Kuang-Kuo
Yen, Wan-Ting
Huang, Jacob C.
Jang, Jason S.-C.
Hsieh, Ker-Chang
Abstract
In recent years the emerge of high-entropy alloys (HEAs) imposes an evolution in metallic materials, which breaks the boundaries set by the traditional alloys. Alongside the development of HEAs, the medium-entropy alloys (MEAs), which comprise two to four majority elements, also reveal the outperforming properties with less compositional complexity. Among them, the medium-entropy AlNbV alloys attract great attention owing to the existence of a body-centered cubic (BCC) solid solution that contains soluble Al, Nb, and V elements. Herein, we construct the phase diagrams for Al-Nb-V system and define the equilibrium homogeneity by thermally-equilibrated ternary alloys underwent a post-annealing at 1073 K or 1273 K. Meanwhile, a superposition of phase diagram and thermal conductivity κ mapping suggests that the coexistence of BCC solid solution and nano-grained AlNb2 brings down the κ. With the incorporation of Ti and Cr, the HEA AlNbVCrTi, which is composed of Laves C14 phase and BCC solid solution, achieves an ultralow κ of 6–10 Wm−1K−1 within 323–723 K. © 2020
Subjects
AlNbV
AlNbVCrTi
High-entropy alloy
Medium-entropy alloy
Phase diagram
Thermal conductivity
Publisher
Elsevier B.V.
Description
論文編號: 100889
Type
journal article