Rank the strength of the following materials from strongest to weakest: carbon fiber, plastic, steel, aluminum

In general, how do these materials rank regardless of specific alloy or configuration.

Strength of materials can hold many meanings. As such, it’s important to denote what type of strength (tensile, compressive, etc.) that you’re using as a benchmark to compare materials.

For tensile strength, the strength of a material is linked to the Yield Strength, defined as a material’s ability to resist being deformed elastically (non-permanently). From strongest to weakest, the materials rank in terms of tensile yield strength as:

  1. Carbon Fiber: 3200 MPa
  2. Steel: 350 MPa
  3. Aluminum: 276 MPa
  4. Plastic: 45 MPa (Nylon)

The strongest carbon fiber composites can be 10x stronger than steel while also being 5 times lighter respectively. Glass-reinforced plastics can be stronger, but for the most part plastics are the weakest in terms of tensile yield strength.

I think it’s important in these situations to define what ‘strong’ means. In materials, ‘Strong’ is a red herring and has no real meaning. There is tensile strength, compressive strength, flexural strength(specifically for plastics), tortional strength, impact resistance.

Clarifying that you’re talking specifically about tensile strength shows that you understand the differences in material properties

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@SnareJunkie Absolutely! That’s a point I was meaning to address because “strong” has multiple meanings. Will fix that in the solution above.

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Carbon fiber > steel > aluminum > plastic for tensile and yield strength

on the ranking you’ve listed carbon fiber’s yield strength to be 3200Mpa, which is 3.2GPa. shouldn’t that be less than steel, with a listed yield strength of 350 GPa(which i think you might have a typo)

Hey @jacker2011, great point! My apologies, I double-checked the numbers used as a reference and Steel’s tensile strength should have been listed in MPa, not GPa. Thanks for pointing out the typo.