NEGATIVE CTE

What is Negative Thermal Expansion?

Thermal expansion refers to a material’s natural increase in size with increasing temperature. While all other metals in the world expand with increasing temperature, ALLVAR Alloys are designed to shrink with increasing temperature. These alloys exhibit 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.

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)
710
276
215
55
828
UTS
(MPa)
750
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. We have received an SBIR to further develop alloys that can withstand higher temperature ranges. If you are interested in a higher temperature alloy, please contact us with more details on your application and desired temperature ranges so we can further the conversation.

Where can I learn more about your alloys?

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