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Castable Amorphous Metal Mirrors and Mirror Assemblies

The novelty of the current work is that tremendous cost and time savings can be achieved by casting the mirror assembly into a net or near-net shape using a metal alloy. This work suggests that mirror assemblies can be cast or fabricated using BMGs or BMGMCs where the entire part can be made using a simple and repeatable processing procedure to form the mirror into the same shape as the conventional mirror assembly, but without the need for machining from a billet. This idea is novel for a number of reasons, including that conventional metal alloys cannot be cast into net shapes without great expense, and this unique class of metal alloys has the ability to be cast, repeatedly, into reusable molds to net shapes and yet still have the hardness and toughness to satisfy the requirements for being used as a mirror assembly. Unlike crystalline metals, BMGMCs also have unique joining properties that allow them to be welded together into solid structures without heat-affected zones, which removes bonding, bolting, and brazing from assembly.

This work has the potential to make a broad impact in the way that mirror assemblies are fabricated for spacecraft, satellites, and terrestrial optics. Since most NASA spacecraft and satellites require optics, the current invention may provide a path for creating high-performance mirrors while greatly reducing their cost. Moreover, the invention may result in an assembly-line-type process for fabricating mirror assemblies that will reduce the cost of terrestrial optics, such as mirrors and telescopes.

The last technique demonstrated is a localized surface treatment as a way to take a near-net shape and turn it into a mirror finish. In this technique, the BMG mirror assembly is fabricated through one of the strategies described above, but the mirror finish is left in a rough state. The mirror assembly is then subjected to a surface treatment that produces an optical mirror surface without machining, grinding, or polishing.

This work was done by Douglas C. Hofmann, Gregory L. Davis, Gregory S. Agnes, and Andrew A. Shapiro of Caltech for NASA’s Jet Propulsion Laboratory. For more information, contact This email address is being protected from spambots. You need JavaScript enabled to view it. .

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:

   Innovative Technology Assets Management
   JPL Mail Stop 321-123
   4800 Oak Grove Drive
   Pasadena, CA 91109-8099
   E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

NPO-48438