# ALLVAR Alloys: Negative Thermal Expansion\. Positive Results\.

> Negative Thermal Expansion ALLVAR alloys assist with the most challenging athermalization and design challenges\. Explore Negative CTE today\!

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## Pages
- [ALLVAR Alloys Home](https://allvaralloys.com/)
- [Washers](https://allvaralloys.com/constant-force-load-allvar-alloys/)
- [Negative CTE Washers](https://allvaralloys.com/negative-coefficient-of-thermal-expansion-products-applications/negative-cte-washers/)
- [Bolt Preload Loss Calculator](https://allvaralloys.com/bolt-preload-loss-calculator/)
- [NEGATIVE THERMAL EXPANSION](https://allvaralloys.com/what-is-negative-thermal-expansion/)
- [Tailored CTE with ALLVAR Alloy M](https://allvaralloys.com/tailored-cte-with-allvar-alloy-m/)
- [NTE Spacers](https://allvaralloys.com/athermalization-made-nte-spacers/)
- [Round Bar and Tube](https://allvaralloys.com/negative-coefficient-of-thermal-expansion-products-applications/round-bar-and-tube/)
- [Ultra\-Stable Struts](https://allvaralloys.com/ultra-stable-struts/)

## Posts
- [Thermal Compensating Washers for CTE Mismatch](https://allvaralloys.com/thermal-compensating-washers-for-cte-mismatch/): Learn how to use negative thermal expansion ALLVAR washers or spacers to maintain a constant preload and tackle CTE mismatch\.
- [Invar vs ALLVAR Alloys: Controlled Thermal Expansion Alloys](https://allvaralloys.com/invar-vs-allvar-alloy/): Invar is an iron\-nickel alloy that exhibits a very low, isotropic CTE while ALLVAR Alloy 30 is a titanium alloy that exhibits a negative CTE\.
- [The Evolution of Athermal Design](https://allvaralloys.com/the-evolution-of-athermal-design/): Athermal design owes its foundations to an 18th century clockmaker's designs\. ALLVAR Alloys will help you revolutionize your design\.
- [Unlocking the Cosmos: ALLVAR's Role in the Nancy Grace Roman Space Telescope](https://allvaralloys.com/allvars-role-in-the-nancy-grace-roman-space-telescope-thermal-conductivity/): ALLVAR is headed to space in a big way\! Find out how ALLVAR Alloys are being used aboard the Nancy Grace Roman Space Telescope to improve thermal conductivity\. 
- [A Year of Growth and Gratitude: 2025 YEAR\-IN\-REVIEW](https://allvaralloys.com/a-year-of-growth-and-gratitude-2025-year-in-review/)

## Videos
- [Reducing the length of athermal optics with ALLVAR Alloys](https://allvaralloys.com/aiovg_videos/the-length-effects-of-materials/)
- [Optics Part 1 \-The Coefficient of Thermal Defocus](https://allvaralloys.com/aiovg_videos/the-coefficient-of-thermal-defocus-part-1/)
- [Jeremy McAllister talks at SPIE AR/VR/MR](https://allvaralloys.com/aiovg_videos/jeremy-mccallister-talks-at-spie-ar-vr-mr/)
- [Dr\. James A\. Monroe Talks about SPIE AR/VR/MR](https://allvaralloys.com/aiovg_videos/dr-james-a-monroe-talks-about-spie-ar-vr-mr/)
- [CTE Part 1 \- Average and Instantaneous Calculations](https://allvaralloys.com/aiovg_videos/average-and-instantaneous-cte-calculations/)

## Categories
- [Negative Thermal Expansion](https://allvaralloys.com/category/negative-thermal-expansion/)
- [Uncategorized](https://allvaralloys.com/category/uncategorized/)
- [Optics](https://allvaralloys.com/category/optics/)
- [Telescopes](https://allvaralloys.com/category/telescopes/)
- [Washers for thermal preload](https://allvaralloys.com/category/washers/)

## Tags
- [Negative Thermal Expansion](https://allvaralloys.com/tag/negative-thermal-expansion/)
- [Athermalization](https://allvaralloys.com/tag/athermalization/)
- [Athermal Design](https://allvaralloys.com/tag/athermal-design/)
- [Thermal Mismatch](https://allvaralloys.com/tag/thermal-mismatch/)
- [CTE Mismatch](https://allvaralloys.com/tag/cte-mismatch/)

## Video Categories
- [Allvar University \- Learn About CTE](https://allvaralloys.com/aiovg_categories/allvar-university-learn-about-cte/)
- [NTE Spacers](https://allvaralloys.com/aiovg_categories/optics-refractive/)
- [Ultra\-Stable Struts](https://allvaralloys.com/aiovg_categories/ultra-stable-struts/)
- [Demos](https://allvaralloys.com/aiovg_categories/demos/)
- [Meet the Team](https://allvaralloys.com/aiovg_categories/meet-the-team/)

## Optional
- [Sitemap index](https://allvaralloys.com/sitemap_index.xml)