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Develop a Repeatable Manufacturing Process for Aerospace Grade Aluminum Alloy Propellant Tanks



TECHNOLOGY AREA(S): Materials/Processes

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 5.4.c.(8) of the solicitation.

OBJECTIVE: Develop and demonstrate a manufacturing process that consistently reproduces an ultra-lightweight propellant tank design from aerospace grade aluminum alloys (e.g. Aluminum 2219, ultra-lightweight aluminum alloy, etc.).

DESCRIPTION: Seek optimized manufacturing process(es) for aerospace grade aluminum alloy tank design to include a high-quality joint in the fabricated structure containing a microstructure consistent with the finished aluminum alloy component. Significant fuel cost savings can be realized in the aerospace industry by employing lightweight materials in the design and fabrication of vehicular components. To date, the exploitation of lightweight aluminum alloys in component fabrication has been restricted due to their limited formability at room temperatures in conventional metal stamping processes. Stir welding is a current process that generates high-quality joints in the fabricated structure and is the baseline joining process for other emerging aerospace aluminum alloy structures such as cryogenic tanks and lightweight structures. This topic seeks improvements to this process or the forming process to produce a more practical, elevated-temperature, rapid-production, manufacturing system for the production of ultra-lightweight aluminum components. Specific areas of interest include incorporating solid state stir welding techniques to enable and expand stir welding to other high-strength, high-temperature alloys using solid state joining. Additional areas of interest include incorporating advancements in ultrasonic vibration technology to facilitate the successful fabrication of the finished propellant tank. Proposed manufacturing process improvements should demonstrate the capability to produce parts to within 0.76 mm (1/30th of an inch) with minimal to no post-process machining for the finished part.

PHASE I: Develop an innovative aerospace grade aluminum alloy fabrication process for production of lightweight propellant tanks. Develop and demonstrate the ability to produce high quality joints and the ability to minimize production non-conformance.

PHASE II: Design, fabricate, and test the prototype elevated-temperature manufacturing system and solid state joining process. The final design should meet the desired level of operational performance and be readily adaptable to future vehicle designs. Computer modeling should be used in conjunction with testing results to optimize process parameters in order to enhance component formability. The prototype should offer flexible control features to allow for process optimization. Verify and validate the finished ultra-lightweight aluminum alloy microstructure relationship to grain size, orientation, service loads, test loads, and mechanical response are adequate for intended operational goals.

PHASE III DUAL USE APPLICATIONS: Develop reliable and repeatable propellant tank fabrication manufacturing processes that are ultra-light weight and compatible with intended operating conditions and dynamic environment. Further commercialize the capability to benefit other DoD Agencies, NASA, and other potential commercial partners.


  • Jeff Ding, Bob Carter, Kirby Lawless, Dr. Arthur Nunes, Carolyn Russell, Michael Suites, and Dr. Judy Schneider. February 14, 2008. "A Decade of Friction Stir Welding R&D At NASA's Marshall Space Flight Center And a Glance into the Future."
  • L.E. Murr, G. Liu, and J.C. McClure. 1997. "Dynamic recrystallisation in the friction-stir welding of aluminum alloy 1100." Journal of Materials Science Letters 16 (22). 1801–1803.
  • R.E. Sanders. 2001. “Technology Innovation in aluminum Products.” The Journal of The Minerals, 53(2). 21–25.

KEYWORDS: solid state stir welding, advanced manufacturing, ultra-lightweight propellant tank


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