Limit to the strength, the hardness, and the density of a material?

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Discussion Overview

The discussion centers on the limits of material properties, specifically the strength, hardness, and density of materials. Participants explore theoretical upper bounds for yield strength and hardness, the potential for creating materials denser than osmium, and the feasibility of constructing machines capable of withstanding extreme conditions such as those found in the Earth's core.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that there may be an upper limit to material strength determined by the strength of molecular or atomic bonds, with real materials often failing below this due to imperfections.
  • There is uncertainty regarding whether diamond represents the limit of hardness, with some suggesting it is close but not definitively the upper bound.
  • Concerns are raised about the ability to create machines that can survive the extreme pressures and temperatures of the Earth's core, noting that many materials lose mechanical strength near their melting points.
  • Participants discuss the possibility of creating materials denser than osmium, with some suggesting that stable heavy atoms beyond atomic number 118 could achieve this, while others assert that osmium is likely the densest 'real' material.
  • There is contention regarding the densities of osmium and tungsten, with some asserting that there is no consensus on which is denser, and others providing references to density values that suggest osmium is slightly denser.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the density of osmium and tungsten, and there is no consensus on the upper limits of material strength and hardness. The discussion remains unresolved on these points.

Contextual Notes

Participants note that the discussion is influenced by the presence of imperfections in materials, the conditions under which materials are tested, and the definitions of density and stability in the context of heavy elements.

Researcher X
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Is there a limit to how strong a material we can create? Does yield strength have an upper bound, and how high is that upper bound above materials created today? What about hardness? Is Diamond the limit?

Could we ever make a machine that could survive the pressures and temperature found in the Earth's core?

I'm also wondering whether it's possible to create a stable material denser than Osmium? Density is distinct from strength, I know, but it's also something I've been wondering.
 
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Researcher X said:
Is there a limit to how strong a material we can create? Does yield strength have an upper bound, and how high is that upper bound above materials created today? What about hardness? Is Diamond the limit?
There is an upper limit which is the strength of the molecular or atomic bond inside the material.
Most real materials fail below this limit due to imperfections, scratches etc. It is possible to make small samples with no flaws that reach the atomic limit. I don't know if diamond is exactly the limit - but it will be something close.

Could we ever make a machine that could survive the pressures and temperature found in the Earth's core?
Not quite, carbon and tungsten melt at around 4500C, the Earth's core is a bit more than that. There is also an issue with the mechanical strength of many materials near their melting point.

I'm also wondering whether it's possible to create a stable material denser than Osmium? Density is distinct from strength, I know, but it's also something I've been wondering.
If any of the very heavy atoms Z>118 turn out to be stable, they will have a higher density. but other than temporarily producing higher densities under very high pressure, or counting collapsed matter in neutron stars or white dwarfs - no Osmium is probably the densest 'real' material.
 
Sounds like we're stuck with what we've got then when it comes to those properties.
 
mgb_phys said:
...Osmium is probably the densest 'real' material.


Or tungsten, depending upon who you ask. There is no consensus on this point.
 
negitron said:
Or tungsten, depending upon who you ask. There is no consensus on this point.

Really? I though tungsten was about the same density as gold.
 
negitron said:
Or tungsten, depending upon who you ask. There is no consensus on this point.

Surely you're thinking of iridium, which has a similar density to osmium? (Tungsten's density is about 10% lower and is similar to gold, as mgb_phys states.)
 

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