NEGATIVE CTE

What is Negative Thermal Expansion?

ALLVAR's negative strain is shown. The negative thermal expansion is the derivitave of this strain with respect to temperature.

Thermal expansion refers to a material’s natural increase in size with increasing temperature. While all other metals in the world expand alongside increasing temperature, ALLVAR Alloys are designed to shrink with increasing temperature. This shrinkage is known as a negative coefficient of thermal expansion.

This revolutionary property can compensate for the expansion or contraction of other materials in the world’s most demanding thermal stability applications. Spaceborne telescopes, high performance optical assemblies, and the secure transport of petrochemicals are a few of the applications that require enhanced stability and performance when operating under extreme shifting thermal environments. 

Negative Thermal Expansion alloys can be used as compensating elements or metering structures to passively athermalize optics or as washers or spacers to maintain a constant-force load across a wide temperature range.

How does ALLVAR compare to other alloys being used?

Property Units ALLVAR Alloy Invar 304 Stainless Steel 6061 Aluminum Titanium 64
CTE Range @20°C
(ppm/°C)
-30
1.6 to 6
17.3
23.6
9
Max Operating Temperature
(°C)
100
200
870
120
540
Yield Stress
(MPa)
405
276
215
55
828
UTS
(MPa)
800
448
505
124
895
Elastic Modulus
(GPa)
75
141
193
68.9
113.8
Density
(g/cc)
5.08
8.1
8.0
2.7
4.42
Thermal Conductivity
(W/m·K)
6.2 - 8.7
10.15
16.2
180
6.6

Do you offer alloys at temperatures higher than 100 degrees C?

Yes. Additional alloys that can withstand higher temperature ranges were developed as part of a NASA SBIR  grant. If you are interested in a higher temperature capable alloy, please contact us with more details on your application and desired temperature ranges so we can find the best athermalization solution for you.

Where can I learn more about your alloys?

You can start by visiting our FAQ page and our video library for demonstrations and discussions.  Our News page also has information about our work to develop struts for NASA telescopes. You can also contact us for more information.

Contact Us Today to Revolutionize Your Thermal Performance

Have an application in mind? Please let us know if you have any questions.

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