I'd like to get some advice for transparent material,
they need to be stiff and tough.
I have tried some plastics but they are not stiff enough, and glass is too brittle.

Thanks!

Transparent in what wavelength window?
Light scattering and inclusions?
Problems with refractive index and Abbe number?
Surface scratch and dig specs?

HOW THICK? WHAT AREA/THICKNESS? What temp? What chemical
environment? What loading? Stress birefringence? For how long?

Toughened polystyrene or crosslinked+toughened acrylic. Pyrex.


You can have stiff (hard, brittle; glassy) or you can have tough
(elongation to failure, notch failure resistance,; leathery). If you
want both, the price just skyrocketed if it can be done at all.

Did you try pMMA (acrylic) or polycarbonate? If the transparency
requirement is not very high you can consider amorphous nylons, and
transparent epoxies.

Single-crystal Indian or Australian muscovite book mica.
Available in crystal-clear flawless sheets and plates from
10 microns to more than 1 centimetre thickness,
more than 1 decimetre diagonal length.

thanks for your reply.
the modulus need to be greater than 20 GPa.

to Mark

the Young's mudulus need to be more than 20 GPa,
I need to make a small thin plate(3mm deep, 20mm diameter) with some
small holes through the plate using the material. and later I will
apply some presure(20 MPa) on the plate. so I am afraid some materials
are too brittle...

Mica isn't brittle at all. A strip 100 micron thick (normal to the
crystal plates) x 1 mm x 100 mm would be easy to tie into a knot.
I could probably tie several knots in that, without breaking it.
You can drill it, along the axis normal to the plates.

20 MPa is no problem, applied evenly. Is that 20 MPa
applied as a liquid or gas? What is its composition?
If it penetrates the mica between the plates, and then
the pressure is suddenly released, and the pressure medium
underwent a liquid-gas transition, the mica could puff up.
That's like vermiculite -- which is mica infiltrated with water,
then puffed by rapid heating.

Hi Mark, thanks for your advice.
I have found some "Muscovite Mica" Rigid Sheets from Mcmaster.
the 10" x 12" x .125" (Part Number 8779K51) for 61.75$. Is this the right mica?

Thanks again!

Mucovite is without question the right mica.
I don't know anything about the McMaster material
or your application, so I can't say whether that material
would work. You'll have to read their specifications.

Note that mica sold for electrical insulating purposes
is often consolidated from smaller pieces
This sort of mica is not transparent. For transparency,
you must use single-crystal book mica.

I can only found 100 micron thick mica on Mcmaster, Where could I
found thicker one like 0.5 or 1 cm?

You might do better with synthetic fluorophlogopite used in steam
boiler sight glasses. The Kirk-Othmer Encyclopedia has a large
section on synthetic mica.

http://www.hcmat.com/Crystal/Mica/Mica.htm
http://www.crystalsland.com/micas.html
<http://www.geo.arizona.edu/AMS/result.php?mineral=Phlogopite>

The company people told me that " the fluorine mica is too soft and
cleavable", is it true?

1) Don't top post.
2) Trust the folks who do the work.

How about some clear casting polyester with glass fiber reinforcement, or
basic clear epoxy with good wetting agent and glassfiber.

Deaerate the wet laminate in vacuum, and press between releasing agent
treated and polished glass plates in vacuum bag. Needs some practice, but
I once made pretty good ones with this technique for control window
purposes.

I am looking for plastic reinforced by glass fiber.
Thanks for your advice!

Henry, Asbestos is what you seek. Dangerous if inhaled though so measures must be taken to prevent it from becoming airborne.

-Scotty