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This Defense Intelligence Reference Document from the Defense Intelligence Agency, dated 12 January 2010, is one of a series of advanced technology reports produced in FY 2009 under the Advanced Aerospace Weapon System Applications (AAWSA) 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, ceramics and titanium aluminides. It concludes that newer materials and design methods offer many ways to improve structural efficiency and cost compared with the space shuttle.
“The Advance”8 pages
UNCLASSIFIED/J1P81l 8PPl!llllt ~Bl! BHl!\7 in materials with small annual sales volume, so even licensing the new material to one of these companies may not be commercially feasible. This foregoing discussion highlights a commonly encountered inconsistency between technical innovation and commercial progress. Until a production-scale source exists, pricing of new materials is at best highly uncertain and potentially unstable over time. This is in part due to the uncertainty surrounding demand and the associated volume of material that will be required. Taken together, these factors act as a clear deterrent to the adoption of new materials of literally all classes (polymers, metals, and ceramics). For heavily loaded structures or structures that will experience temperatures higher than about 200 °Celsius, Ti alloys are the preferred material class. Ti alloys are about half as dense as steel or Ni-base alloys and possess a density-corrected strength and stiffness competitive with that of other metallic materials. Numerous grades of Ti alloys are in use today, and a strong domestic industrial base of suppliers exists for nearly all these grades. Ti alloys for structural applications can be divided into three groups based on their metallurgy: near a alloys, a:+p alloys, and metastable i~ alloys (commonly called ~ alloys for short}. Both the aircraft and propulsion original equipment manufacturers and several private engineering firms have extensive design experience with Ti alloys. Although most of this experience is with Ti-6Al-4V (Ti-6-4 ), other alloys also are widely used, particularly in jet engines and liquid-fueled rocket engines. The alloy most likely to be used in a launch vehicle, Ti-6-4, has been available and in use for more than 40 years but is still highly competitive with newer grades in large part because of its versatility. Potential applications of other alloys that have particularly attractive characteristics, such as a higher temperature capability, are discussed in the Reusable Reentry Vehicle and Propulsion Systems sections of this document. The most commonly used structural grade of Ti alloy today, Ti-6-4, can be readfly fusion welded, formed both by forging and as a sheet product, and conventionally machined, although each of these operations requires special precautions. In addition, the feasibility of friction stir welding has been demonstrated. Ti-6-4 also can be superplastically formed and diffusion bonded, enabling synthesis of innovatively shaped components. For launch vehicles, the most likely application for Ti alloys is in the structure that carries the reactions from the propulsion system to the vehicle itself. These applications typically involve heavy sections to accommodate the large loads, and the main property requirements are high strength, fatigue resistance, and fracture toughness. Ti alloys have been used in both military and commercial aircraft. Heavily loaded components in service today include the wing box of the B-16 bomber (Ti-6-4), the landing gear beam in the B-747 (Ti-6-4), and the landing gear truck beam in the B- 777 (higher strength Ti-10V-2Fe-3AI [Ti-10-2-3]). The choice of Ti-10-2-3 for the landing gear truck beam reflects the time-based maturation of the newer B-Ti alloys, such as Ti-10-2-3. These alloys have the advantage of being "deep hardenable"- compared with Ti-6-4, they can develop full strength in thicker sections during heat treatment. For example, that the B-777's truck beam is up to 6 inches thick in some locations factored significantly in the choice of Ti-10-2-3. Because Ti alloys are about half as dense as steet they are very competitive on a density-corrected basis. However, mass is not the only driver for some applications; the volume of a component also must be compatible with the space available for it. This factor also is a consideration in the choice of Ti-10-2-3 for the B-777 truck beam. And it also applies to an application such as landing gear, because it is retracted into the fuselage for aerodynamic reasons. 7 UNCLASSIFIED//502 PEFICJOI 1166 0111 ¥
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Report, from the dia 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.