High thermal stability of the amorphous structure of GexNbTaTiZr (x=0.5, 1) high-entropy alloys

Cheng, Chien-Hong

doi:10.1016/j.matlet.2016.06.040

Cited by 37 publications

(6 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, not all HEAs can form a single phase solid solution microstructure. In many cases, the formation of ordered intermetallic phases, complicated compounds or even amorphous phases was often observed 20 – 23 .The formation rules of different phases in HEAs have been widely studied for many years, but the factors controlling phase formation are still under debate 24 – 29 . In order to optimize the microstructure for desired properties, a common strategy employed until now has been to design multicomponent alloys with equiatomic or near-equiatomic compositions.…”

Section: Introductionmentioning

confidence: 99%

Design of non-equiatomic medium-entropy alloys

Zhou

Jin

et al. 2018

Sci Rep

View full text Add to dashboard Cite

High-entropy alloys have attracted much attention due to their unique microstructures and excellent properties. Since their invention more than ten years ago, research attention has been mainly focused on the study of multicomponent alloys with equiatomic or near-equiatomic compositions. Here we propose a novel design of non-equiatomic medium-entropy alloys that contain one matrix element and several equiatomic alloying elements. To verify the utility of this new design, a series of Co-free Fex(CrNiAl)100−x (at.%, 25 ≤ x ≤ 65) medium-entropy alloys were designed from the much-studied FeNiCrCoAl high-entropy alloy. Detailed characterization reveals that the alloys exhibit novel two-phase microstructures consisting of B2-ordered nanoprecipitates and BCC-disordered matrix. As the alloys deviate far from equiatomic composition, the structure of the nanoprecipitates transfers from a spinodal-like intertwined structure to a nanoparticle dispersed structure. Previous parametric approaches to predict phase formation rules for high-entropy alloys are unable to describe the phase separation behaviors in the studied alloys. Our findings provide a new route to design medium-entropy alloys and also demonstrate a strategy for designing nanostructured alloys from multicomponent alloy systems through simple variations in non-equiatomic compositions.

show abstract

Section: Introductionmentioning

confidence: 99%

Design of non-equiatomic medium-entropy alloys

Zhou

Jin

et al. 2018

Sci Rep

View full text Add to dashboard Cite

show abstract

“…They observed the coatings remained stable even after annealing at 900 C for 8 h, and attributed the oxidation resistance of HEA coating to the formation of NiO and the alloying elements: Al, Cr, and Co. Dolique et al [238] reported the stability of AlCrFeCoNiCu HEA thin film up to 510 C using in-situ XRD. Cheng et al [73,239] demonstrated a remarkable thermal stability of amorphous structure in Ge x TiZrNbTa and BTiZrNbTa HEAs thin film after annealing in the temperature range of 700-800 C for 1 h in a vacuum. They attributed the exceptional thermal stability of amorphous structure to the combination of high entropy, significant atomic size differences, and enhanced sluggish diffusion.…”

Section: Thermal Stability Of Hea Coatingsmentioning

confidence: 99%

High‐Entropy Alloys: Potential Candidates for High‐Temperature Applications – An Overview

2017

View full text Add to dashboard Cite

Multi-principal elemental alloys, commonly referred to as high-entropy alloys (HEAs), are a new class of emerging advanced materials with novel alloy design concept. Unlike the design of conventional alloys, which is based on one or at most two principal elements, the design of HEA is based on multi-principal elements in equal or near-equal atomic ratio. The advent of HEA has revived the alloy design perception and paved the way to produce an ample number of compositions with different combinations of promising properties for a variety of structural applications. Among the properties possessed by HEAs, sluggish diffusion and strength retention at elevated temperature have caught wide attention. The need to develop new materials for high-temperature applications with superior high-temperature properties over superalloys has been one of the prime concerns of the high-temperature materials research community. The current article shows that HEAs have the potential to replace Ni-base superalloys as the next generation hightemperature materials. This review focuses on the phase stability, microstructural stability, and high-temperature mechanical properties of HEAs. This article will be highly beneficial for materials science and engineering community whose interest is in the development and understanding of HEAs for high-temperature applications.

show abstract

“…Quantifying atomic diffusion in MPEAs is important, as the solid-solution phase with the highest mixing entropy does not always have the lowest Gibbs free energy [24] and complex phases may precipitate in MPEAs after annealing treatments. For example, Cheng et al [25,26] attribute the remarkable thermal stability of the amorphous structure in Ge x TiZrNbTa and BTiZrNbTa thin films to the combination of high entropy, significant atomic size differences, and sluggish diffusion. In [27], Zhao et al studied the coarsening of L1 2 precipitates in a face-centered-cubic (NiCoFeCr) 94 Ti 2 Al 4 MPEA at temperatures ranging between 750 • and 825 • C. They concluded that, owing to sluggish diffusion, L1 2 precipitate coarsening was much slower in the MPEA than in conventional Ni-based alloys.…”

Section: Introductionmentioning

confidence: 99%

Vacancy Diffusion in Multi-Principal Element Alloys: The Role of Chemical Disorder in the Ordered Lattice

Thomas

Patala

2020

SSRN Journal

View full text Add to dashboard Cite

Many of the purported virtues of Multi-Principal Element Alloys (MPEAs), such as corrosion, high-temperature oxidation and irradiation resistance, are highly sensitive to vacancy diffusivity. Similarly, solute interdiffusion is governed by vacancy diffusion -it is often unclear whether MPEAs are truly stable, or effectively stabilized by slow interdiffusion. The considerable composition space afforded to these alloys makes optimizing for desired properties a daunting task; theoretical and computational tools are necessary to guide alloy development. For diffusion, such tools depend on both a knowledge of the vacancy migration barriers within a given alloy and an understanding of how these barriers influence vacancy diffusivity. We present a generalized theory of vacancy diffusion in rugged energy landscapes, paired with Kinetic Monte Carlo simulations of MPEA vacancy diffusion. The barrier energy statistics are informed by nudged elastic band calculations in the equiatomic CoNiCrFeMn alloy. Theory and simulations show that vacancy diffusion in solid-solution MPEAs is not necessarily sluggish, but can potentially be tuned, and that trap models are an insufficient explanation for sluggish diffusion in the CoNiCrFeMn MPEA. These results also show that any model that endeavors to faithfully represent diffusion-related phenomena must account for the full nature of the energy landscape, not just the migration barriers.

show abstract

High thermal stability of the amorphous structure of GexNbTaTiZr (x=0.5, 1) high-entropy alloys

Cited by 37 publications

References 20 publications

Design of non-equiatomic medium-entropy alloys

Design of non-equiatomic medium-entropy alloys

High‐Entropy Alloys: Potential Candidates for High‐Temperature Applications – An Overview

Vacancy Diffusion in Multi-Principal Element Alloys: The Role of Chemical Disorder in the Ordered Lattice

Contact Info

Product

Resources

About