Preprint Technical Note Version 1 Preserved in Portico This version is not peer-reviewed

Fracture of Be and Its Alloys - Webb Space Telescope Revisited

Version 1 : Received: 25 November 2021 / Approved: 26 November 2021 / Online: 26 November 2021 (11:33:12 CET)

How to cite: Rafique, M.M.A. Fracture of Be and Its Alloys - Webb Space Telescope Revisited. Preprints 2021, 2021110503 (doi: 10.20944/preprints202111.0503.v1). Rafique, M.M.A. Fracture of Be and Its Alloys - Webb Space Telescope Revisited. Preprints 2021, 2021110503 (doi: 10.20944/preprints202111.0503.v1).

Abstract

NASA/ESA/CSA joint venture James Webb Space Telescope is about to be launched. It is hypothesized to operate in near-infrared range. It is also hypothesized to unveil early star formation, galaxies, and universe due to its orbit, point in orbit and orbital motion. It has been under manufacturing for over 20 years at a staggering cost of 10 billion US dollars (most expensive scientific experiment in history). Beryllium (Be) is chosen to be element for construction of its main mirrors due to its high stiffness, low density, low linear coefficient of thermal expansion (α) in cryogenics and high thermal conductivity. It is followed by gold (Au) layer deposition on its (Be) surface to enhance its sensitivity towards infrared radiation as later is hypothesized to bear superior properties. However, serious mistakes have been made in selecting this material for this application. Owing to its crystal structure (hexagonal close packed (hcp)), slip planes (basal, prismatic and pyramidal) and mechanisms of their activation, Be necessitates easy fracture at cryogenic temperature. It has anisotropic properties and prone to transverse fracture under tensile loading. Furthermore, its ductile to brittle transition temperature is very low making it entirely unsuitable for such an application. It is one of most expensive metals on planet. This study constitutes revisiting these fundamental properties and mechanisms which were entirely ignored during materials selection thus rendering whole project useless.

Keywords

Crystal structure; hexagonal close packed; slip planes; anisotropy; fracture

Subject

ENGINEERING, Other

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