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This Defense Intelligence Reference Document, dated 14 December 2009, was prepared by the Defense Intelligence Agency's Defense Warning Office under its Advanced Aerospace Weapon System Applications program. It is a technical review of metallic glasses that covers their structure, processing, mechanical behavior and possible aerospace uses. It concludes that composites with ductile dendrites in a glass matrix hold the most promise for structural use. It also finds that widespread aerospace adoption depends on developing new lightweight glass-forming alloys.
From the source: Release of 2026-09-18 Incident: 12/14/09, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD surveys metallic glasses as a potentially important class of aerospace materials and describes their amorphous structure as offering very high strength and unusual manufacturing advantages, but also significant drawbacks, especially poor ductility and fatigue resistance. The document concludes that the most promising aerospace applications are likely to come from metallic-glass-matrix composites rather than single-phase glasses, because these composites can retain high strength while greatly improving fracture toughness and fatigue performance, potentially enough to substitute for high-strength steels in some space-limited structural uses. At the same time, the report judges that broader aerospace use will depend on substantial progress over the next 20–50 years in alloy design, processing, and especially the development of lightweight systems, including aluminum-based options.
..c UNCLASSIFIED//fOR Offl@IAL Wfi& 0PU1¥ bJ) C - ~en a) 4.....en C a) ..... 2a) .....c,;j E..... -5 +-' a) "O :::J 4..... ;.::: 0.. 8 2c,;j en en a) 0.01tl Dendritic composite ...... -- - - - - High-strength steel ingle-pha e metallic gla a ..... Cl') Number of cy le to failure Figure 5. Fatigue Limit of Metallic Glasses and Metallic-Glass-Matrix Composites. Fatigue life data for single-phase zirconium -based metallic glass (red) and a dendrltlc metallic glass matrix composite (blue). Representative data for steel (300-M) of similar tensile strength are shown for comparison .17 16 19 Wear Resistance Because of their high yield strength, metallic glasses also have very high hardness. This, in turn, implies they might have good tribological behavior, which would be of particular interest when combined with the good corrosion resistance of some alloys (see below), opening up potential applications such as coatings on dry bearings for space applications. 20 However, the tendency of metallic glasses to form shear bands and (in some cases) partially crystallize owing to deformation means their wear resistance is perhaps not as good as their high hardness would suggest. Nevertheless, the wear resistance of metallic glasses can still be quite good, and in fact one of the principal current markets for amorphous al loys is as wear- and corrosion-resistant coatings for tools such as drill bits. Corrosion and Stress- Corrosion Cracking It is frequently stated that metallic glasses have excellent corrosion resistance, but this is not always true. The lack of grain boundaries and second-phase particles makes some metallic glasses extreme ly resistant to corrosion, but th is is not true of all alloys (some of which oxidize rapidly in air). Broadly speaking, the corrosion resistance of nickel- and iron-based metallic glasses is better than that of alloys based on zirconium, titanium, and copper (particularly in environments containing chloride ions) .21 Some alloys are susceptible to localized pitting corrosion, probably facilitated by the presence of crystalline inclusions. 10 UNCLASSIFIED/ /5i0A: 05i5ilCIOP !!SF ON! X
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 30 pages are in the text index: search them above, or from the library's search.