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This Defense Intelligence Reference Document, DIA-08-0912-008, is dated 12 January 2010. It was prepared by the Defense Warning Office's Acquisition Support Division at the Defense Intelligence Agency as one of a series of FY 2009 technology reports under the Advanced Aerospace Weapon System Applications program. It reviews materials for launch vehicles, space vehicles and reusable rocket engines, including aluminum alloys, polymer and metal matrix composites, titanium and nickel alloys, and titanium aluminides. It concludes that newer materials and integrated design could improve on the space shuttle.
From the source:Release of 2026-09-18 Incident: 1/12/10, 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 the structural materials needed for advanced aerospace platforms and argues that material choice cannot be separated from overall vehicle design, because launch vehicles, space vehicles, reusable systems, and propulsion hardware each face different temperature, durability, weight, and manufacturing constraints. The report reviews a range of candidate material classes, including advanced aluminum alloys; polymer-, aluminum-, and titanium-matrix composites; titanium alloys; nickel-base alloys; refractory metals; ceramic-matrix composites; carbon-carbon composites; and titanium aluminides. It emphasizes that balancing performance against practical limits such as fabrication methods, cost, inspection, contamination control, and service environment remains a major challenge. Its overall conclusion is that many promising materials exist, but their usefulness depends on application-specific tradeoffs and on closer integration of material selection with design and manufacturing, with some systems judged to be more valuable targets for development than others.
UNCLASSIFIED/ /PO" orr1e11tt U.!I! l>flt I inception. In fact, Ni-base alloys are a prime enabler of the modern gas turbine engine. As a result, this class of materials has a well-established industrial base for the production of literally all product forms. There is a second class of Ni-base alloys that has excellent resistance to attack in aggressive environments, such as those encountered in petroleum recovery, but these alloys are not of interest for high temperature applications. To avoid any confusion, the term Ni-base alloys is used in this document to mean high-temperature Ni -base alloys. Ni-base alloys have a high elevated temperature strength because they typically contain Al and Ti, which enable them to be precipitation strengthened. The alloys with the highest temperature capability are strengthened by precipitates of Ni3AI (called y'), which have a positive temperature coefficient of strength up to about 1,000 °Celsius. This unusual characteristic accounts for Ni-base alloys' elevated temperature capability. In combination with the ord inary temperature dependence of the matrix strength, the overall temperature dependence is quite low compared with that of any other class of structural alloys. Ni-base alloys also contain alloying additions of refractory elements such as tungsten (W), tantalum (Ta), and niobium (Nb). These additions also improve the elevated temperature strength because they diffuse slowly and strengthen the matrix. Because Ni -base alloys are used at elevated temperatures, they contain Cr additions in significant concentrations to improve their oxidation resistance. The tailoring of the properties of Ni-base alloys has been studied extensively and is quite well understood empirically, albeit less so in a fundamental sense. Current-generation Ni-base alloys contain as many as 10 alloying additions, and interelement interactions make gaining a fundamental understanding of alloying effects a major challenge. Production of Ni-base alloys has evolved over several decades . Both ingot metallurgy and powder metallurgy methods are used to produce a full range of mill products. New alloys have periodically been introduced in response to specialized needs. Sometimes these alloy development efforts have been so focused on the "specialized need" that retention of other generally accepted Ni-base alloy properties has been overlooked. An example of this is the development of early " low coefficient of thermal expansion" (a) alloys (the so-called low-a alloys) . An example of an application for which low-a alloys are attractive is structures in which there are two or more concentric rings connected by radial struts. In the presence of a radial temperature gradient, these alloys tend to crack during thermal cycling situations owing to "thermal fatigue." In principle, the availability of an "Invar type" alloy with structural characteristics reduces the thermal strains and improves the thermal fatigue life. Invar is so named because it uses the magnetic characteristics of Ni to offset normal therma l expansion, resulting in much lower a values. It was recognized that this concept could also be adapted to Ni-base structural alloys. The first-generation low-a alloy, Inco 903, had about half the coefficient of thermal expansion compared with ordinary Ni-base alloys up to the Curie temperature. This remarkable alteration of a physical property was achieved by removing the Cr from the alloy to intensify the magnetic effects of magnetostriction. An unfortunate, unintended consequence of this composition alteration was that the oxidation resistance was seriously degraded. In particular, Inco 903 had a propensity for intergranular cracking in air under stress, rendering it of limited utility as a structural alloy. In fact, the cracking was so severe it was given a name: stress assisted grain boundary oxidation (SAGBO) . A second -generation low-a alloy, Inco 909, contained Si to help improve the oxidation resistance, but t his alloy has not gained widespread acceptance, possibly because Inco 903 problems were so severe. Low-a 17 UNCLASSIFIED/ /EOA: OliFICil.\k W&lii 8HL\«
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 27 pages are in the text index: search them above, or from the library's search.