Transparent material with very high yield strenght

[Rulji]

Hi
I'm looking for a material with at very high yield strength, about 500 mPa. At the same time it has to be transparent. Does anyone know any material with these properties?

 

[RPstress]

Glass? Corning's Gorilla glass might be strong enough and at 0.67 MPa.root(m) it at least has a measured toughness.

http://www.corninggorillaglass.com/...Corning Gorilla Glass 4_PI Sheet_011415_D.PDF

.

If you use glass you may have to reinterpret your structural needs, because it's almost impossible to get a supplier to admit what sort of strength their brittle material can give (and arguably it's meaningless). Corning is happy to supply the KIc so you can work out the minimum strength with a small crack in your component (or conversely the maximum crack size allowable for a given applied stress).

Here is some guidance on glass strength:

http://glassproperties.com/references/MechPropHandouts.pdf

If all you need is translucency then glass fiber reinforced polymer might do (a 0° twill weave might give at least 450 MPa).

500 MPa (72.5 ksi) is well above any unreinforced polymer that I know of.

There are one or two other ceramics that might do; sapphire can be transparent. And of course diamond. These have the same problems of brittleness that glass does and will be much more expensive.

 

[RPstress]

Have you considered a structure with reinforced hole and a window? Good steel or carbon fiber composite will give capability of 500 MPa even with half the section as non-load-carrying penetration.

 

[Demon3]

To add to what RPstress said. If you add glass fiber to a polymer matrix with the same refractive index as the glass (i.e. PMMA) then the composite would remain transparent.

Chris DeArmitt PhD
President - Phantom Plastics LLC

Trusted adviser to leading companies around the world

http://www.phantomplastics.com

 

[RPstress]

That might work. I didn't know polymers could be so close to fiberglass. Be worth an experiment?

http://www.ceramicindustry.com/ext/resources/CI/Protected/Files/PDF/fiberglass-compositions.pdf

To match the strength you think you need, S-glass (or R-glass or S-2 glass) might be more appropriate than common-or-garden E-glass (if you can afford them).

Suspect a lot will depend on the clarity needed.

Not sure of the best way to manufacture a continuous fiber PMMA laminate.

 

[RPstress]

Spinel looks like a promising relatively tough transparent ceramic.

https://www.jim.or.jp/journal/e/pdf3/46/05/996.pdf

KIc 1.65 to 2 MPa.rt(m)

2 is still pretty brittle compared with metal or composite though. May not be too dissimilar to unreinforced PMMA:

http://doc.utwente.nl/85336/2/TC4_Tensile_impact_paper_second_revision_including_images.pdf

seems to indicate 1 to 2. This should be enough not to compromise a glass/PMMA composite's properties.