Precise control of negative thermal expansion in stainless invar type alloy for astronomical telescopes

Hiromichi T. Fujii; Naoki Sakaguchi; Kotaro Ona; Yutaka Hayano; Fumihiro Uraguchi

doi:10.1117/12.2561193

13 December 2020 Precise control of negative thermal expansion in stainless invar type alloy for astronomical telescopes

Hiromichi T. Fujii, Naoki Sakaguchi, Kotaro Ona, Yutaka Hayano, Fumihiro Uraguchi

Author Affiliations +

Proceedings Volume 11451, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV; 1145118 (2020) https://doi.org/10.1117/12.2561193
Event: SPIE Astronomical Telescopes + Instrumentation, 2020, Online Only

Abstract

Thermal expansion characteristics of Fe₃₉Co₅₁Cr₁₀ based stainless invar alloys were investigated with the aim of developing a novel structural material used at cryogenic temperature for infrared instruments mounted on astronomical telescopes. Ni-added stainless invar type alloys Fe₃₉Co₄₉Cr₁₀Ni₂ were found to exhibit anomalous thermal expansion behavior in the low temperature range between 100 K and room temperature. According to the measured thermal expansion curves, these alloys expanded with increasing temperature from approximately 100 K to 200 K and contracted from 200 K to 300 K. The coefficients of thermal expansion in each temperature range were estimated to be approximately 0.93 x 10^-6 /K and −0.71 x 10^-6 /K, respectively. As the results of thermal expansion measurements of Cr based alloys, similar negative thermal expansion behavior was observed in the same temperature range between 200 K and 300 K. These findings suggest that the Cr element plays a key role in the negative thermal expansion in the Fe₃₉Co₄₉Cr₁₀Ni₂ alloys. We concluded that the dimensional change between 100 K and room temperature could be precisely controlled in the extremely low thermal expansion range by controlling the negative thermal expansion. The coefficient of thermal expansion between 100 K and 300 K was achieved to be approximately 0.13 x 10^-6 /K in the Fe_38.4Co_49.7Cr_10.1Ni_1.8 alloys developed in this study. As this value was close to that of the fused silica used for infrared instruments, the developed alloys can be a powerful tool for high precision observation in astronomical telescopes.

Conference Presentation

Citation Download Citation

Hiromichi T. Fujii, Naoki Sakaguchi, Kotaro Ona, Yutaka Hayano, and Fumihiro Uraguchi "Precise control of negative thermal expansion in stainless invar type alloy for astronomical telescopes", Proc. SPIE 11451, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV, 1145118 (13 December 2020); https://doi.org/10.1117/12.2561193

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available