High-entropy alloys?

[max808]

From my limited understanding they use 4 or more elements in equal measure so for example you would get
20% Cu
20% Fe
20% Ni
20% Al
20% Cr
Apparently this results in a perfekt distribution of all the elements inside the core matrix as opposed to the outer edges. Some of these high-entropy alloys display characteristics like superparamagnetism and superconductivity. Not entirely sure what that means but it sounds intriguing.

[legOFwhat?]

It has super in it so it has to be good!

Way out of my depth I'm sure!

[max808]

Exactly my reasoning, no official word yet but I started thinking maybe it has something to do with that experimental new ceramic alloy that's being developed. One more attribute of some high-entropy alloys is they are very hard but less brittle so less likely to break.

[mmadison]

My understanding is that the process has huge implied potential, but no successful use-case at scale as of today, due to extremely high cost of development, and little known capital investment. It is largely stuck in academia, as far is has been publicly disclosed.

[Bill1170]

Is this related to so-called “liquid metal” alloys that solidify without crystallizing? They form a metallic glass, in the sense that glass has no crystal structure. The idea seems to be that the wildly variable alloying elements can’t agree on a crystal format as the melt is cooling, so one never forms. Metallic glasses have some promising properties and research is ongoing to develop practical applications.

[Larrin]

High entropy alloys are a hot topic for metallurgists and materials scientists right now, mostly at the University research level. They are not similar to "liquid metal" as those are non-crystalline while high entropy alloys have a crystal structure. I have not seen any high entropy alloys in the literature that rival steels at this point. But because it is so new they are looking at properties all over the map not typically looking for a tool steel or stainless tool steel replacement. I did find a couple of papers where they compared wear resistance of a few high entropy alloys against some tool steels like 52100 or M2 where they could compare favorably: https://www.sciencedirect.com/science/a ... 5411004551
https://www.frontiersin.org/articles/10 ... 787729/pdf

But there wasn't any measurement of toughness so who knows how they would compare there. That is without considering cost of production, difficulty of production, etc. So in general I think we can keep tabs on high entropy alloy research but as of yet it is in the laboratory/exploration stage.

[max808]

Thank you guys for sharing your insights, much obliged. Not sure how this popped up on my YouTube feed... maybe from watching too many CruWear videos. There's some interesting lectures you can watch online but most of it is also way over my head. Does alloy require aluminum to be used in the composition? Around here the word alloy is commonly used for steel in general but I've noticed across the pond that it mostly refers to aluminum based alloys. Looking forward to learn more...

[RustyIron]

High entropy alloys are a hot topic for metallurgists and materials scientists right now,

When discussing these materials, what is meant by "high entropy?"

[metaphoricalsimile]

When discussing these materials, what is meant by "high entropy?"[/font]

One of the almost-but-not-quite-the-complete-picture ways to think of entropy is as the number of configurational states that exist in a system. If an alloy like this has a similar amount of a variety of elements, then you're going to increase the number of configurations of those elements (i.e. their chemical and spatial relationships to one another), thus increasing the entropy of the system as a whole. Granted I don't have a metallurgy background, but I do have a chemistry and materials background (mostly polymers) but this is my understanding based on that.

[bleasure]

High entropy alloys are a hot topic for metallurgists and materials scientists right now,

When discussing these materials, what is meant by "high entropy?"

short answer: it means something like 'really evenly distributed'

long answer: entropy as a thermodynamic principle, esp as translated through cybernetics and information theory, is a measure of what you could call something like organization or 'order' vs. randomness, or in other words, it's a measure of difference and non-difference. Maxwell's demon, for instance, was a thought experiment where a little demon controls a basically magical, weightless gate separating two chambers, each containing an equal distribution (high entropy) of particles in different energy states. the demon sorts those different particles out using the gate until one chamber is filled with high energy (hot) and another low energy (cold) particles, producing a situation of low entropy. so you can see how the principle of entropy as heat-energy is conntected to a notion of 'organization' in physics/matter: the greater the organization or differentiation, the lower the entropy. the 'heat-death of the universe' represents theorized future state of complete entropy, which you might imagine in terms of every atom in the universe being perfectly randomly distributed among all others, to a point of pure non-organization of matter.

Claude Shannon's influential 'signal vs. noise' model of communcation, and Norbert Wiener's description of cybernetics in terms of self-organization via feedback (control) and a tendency towards entropy (un-control so to speak) in cybernetic (i.e. self-organizing) systems, both point to what the word entropy signifies in this phrase: an evenness of elemental distribution that approaches 'purity' so to speak.

[max808]

High entropy alloys are a hot topic for metallurgists and materials scientists right now,

When discussing these materials, what is meant by "high entropy?"

short answer: it means something like 'really evenly distributed'

long answer: entropy as a thermodynamic principle, esp as translated through cybernetics and information theory, is a measure of what you could call something like organization or 'order' vs. randomness, or in other words, it's a measure of difference and non-difference. Maxwell's demon, for instance, was a thought experiment where a little demon controls a basically magical, weightless gate separating two chambers, each containing an equal distribution (high entropy) of particles in different energy states. the demon sorts those different particles out using the gate until one chamber is filled with high energy (hot) and another low energy (cold) particles, producing a situation of low entropy. so you can see how the principle of entropy as heat-energy is conntected to a notion of 'organization' in physics/matter: the greater the organization or differentiation, the lower the entropy. the 'heat-death of the universe' represents theorized future state of complete entropy, which you might imagine in terms of every atom in the universe being perfectly randomly distributed among all others, to a point of pure non-organization of matter.

Claude Shannon's influential 'signal vs. noise' model of communcation, and Norbert Wiener's description of cybernetics in terms of self-organization via feedback (control) and a tendency towards entropy (un-control so to speak) in cybernetic (i.e. self-organizing) systems, both point to what the word entropy signifies in this phrase: an evenness of elemental distribution that approaches 'purity' so to speak.

Thank you bleasure and Dr. Larrin for your enlightening replies. So a grade of purity for a steel's atomic structure if I understand correctly. The different spectrometer shots clearly showed an even distribution of the elements across the board. High production cost is a lil puzzling since you can currently buy a kit online to try and create your own high entropy alloy. Could have something to do with the low success rate to get that perfect sample.