Multi-Component High-Entropy Alloy Phase Stability

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Solution Overview

Problem

Multi-component high-entropy alloys (HEAs) with more than four metal elements face challenges in maintaining a single phase solid solution structure due to phase separation and intermetallic compound formation, limiting their practical application in high-temperature structural materials.

Innovation Solution

Development of a new family of multi-component solid solution HEAs comprising elements like V, Nb, Ta, Ti, Mo, W, and Re, with compositions where relative amounts of each element vary by no more than ±15 atomic %, utilizing a guideline based on binary phase diagrams to ensure large solid solubility regions and minimize intermetallic compound formation, allowing for the creation of single phase alloys with BCC crystal structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multi-component high-entropy alloys with more than four metal elements are created, then high entropy of mixing and unique physical properties are achieved, but phase separation and intermetallic compound formation occur

Engineering Contradiction:

Improvenumber of elementsVSAvoidsingle phase solid solution structure

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by systematically varying the composition ratios of multiple metal elements (V, Nb, Ta, Ti, Mo, W, Re) to achieve a stable single-phase solid solution structure. By optimizing the atomic percentages of each element within specific ranges, the alloy maintains high entropy of mixing while preventing phase separation and intermetallic compound formation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite multi-component alloy system combining seven different metal elements in specific proportions. This composite material approach allows the alloy to exhibit high entropy of mixing and unique properties while maintaining structural stability through the synergistic interaction of multiple elements in a solid solution phase.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If elements are mixed in equiatomic ratio to maximize mixing entropy, then high entropy of mixing is achieved, but lattice distortion increases due to atomic size misfit

Engineering Contradiction:

Improvemixing entropyVSAvoidlattice distortion

Core Design Contradiction:

Quantity of substanceVSShape

Solution Approach 1:

The patent optimizes the composition parameters by adjusting the atomic percentages of each element rather than using strict equiatomic ratios. This allows maximization of mixing entropy while controlling lattice distortion by selecting elements with complementary atomic sizes and adjusting their proportions to minimize atomic size misfit effects.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If traditional solid solution alloys with 2 to 3 elements are used, then simpler composition and easier manufacturing are achieved, but lower strength and temperature resistance are obtained

Engineering Contradiction:

Improvecomposition simplicityVSAvoidhigh temperature strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent transitions from traditional binary or ternary alloys to a heptary multi-component system, creating a composite material that combines seven different metal elements. This composite approach enables the alloy to achieve superior high-temperature strength and structural stability that cannot be obtained with simpler compositions, while still maintaining manufacturability through controlled processing methods.

Inventive Principle:

Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The new family of HEAs exhibits high melting temperatures, high density, and exceptional mechanical properties, including high hardness and strength, making them suitable for high-temperature structural applications and potentially useful in materials requiring high penetration capability.

Implementation Method 1

Solid solution strengthening is one of the most important methods to enhance the strength of materials by alloying other elements into pure metals but still remain entirely as a solution. The strengthening effect is achieved by interacting a solute atom with dislocations either through an atomic size misfit or a modulus misfit.

Methodology Applied

Scientific EffectSolid solution strengthening: Solid Solution Strengthening

Implementation Method 2

When all elements in an alloy have an equal atomic ratio, the configuration entropy (also called mixing entropy), ΔSmix, will reach its maximum value ΔSmix=RInN (N is the number of elements and R the gas constant).

Methodology Applied

Scientific EffectEntropy of mixing:

Data Source

PatentUS9150945B2Multi-component solid solution alloys having high mixing entropy

Publication Date: 2015.10.06 UT BATTELLE LLC

AI summary

A multi-component high-entropy alloy includes a composition selected from the following group: VNbTaTiMoWRe, VNbTaTiMoW, VNbTaTiMoRe, VNbTaTiWRe, VNbTaMoWRe, VNbTiMoWRe, VTaTiMoWRe, NbTaTiMoWRe, VNbTaTiMo, VNbTaTiW, VNbTaMoW, VNbTiMoW, VTaTiMoW, NbTaTiMoW, VNbTaTiRe, VNbTaMoRe, VNbTiMoRe, VTaTiMoRe, NbTaTiMoRe, VNbTaWRe, VNbTiWRe, VTaTiWRe, NbTaTiWRe, VNbMoWRe, VTaMoWRe, NbTaMoWRe, VTiMoWRe, NbTiMoWRe, TaTiMoWRe, wherein relative amounts of each element vary by no more than ±15 atomic %.