High Temperature Tensile Testing

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Hypersonics; Advanced Materials The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: The goal of this topic is to develop methods to test the mechanical properties of materials at temperatures up to 3000 C. DESCRIPTION: Hypersonic leading edge surfaces and propulsion materials push the limits of requirements of high strength at high temperatures. Proper design of components requires mechanical property data for all temperatures that the component may experience. Performing tensile tests at high temperatures may require the use of refractory materials and cooling of tools to hold the sample, but as the temperature for testing increases, the available materials of construction for the test equipment are limited. Accurately measuring the mechanical properties of a sample at a given temperature requires that the sample specimen is as close as possible to isothermal in the region experiencing strain. Heating methods which are not limited by the thermal or electrical conductivity are preferred. Any cooling of the equipment used to hold the sample specimen needs a method of minimizing the heat transfer from the sample. The test method should achieve high quality data including suitable strain measurement, while maintaining uniform heating of the test sample in the gauge section during testing. PHASE I: Design a system to achieve high quality strain measurement data on samples from room temperature to 3000 C under applied stresses of up to 300 MPa at 3000 C. The proposed system should be capable of measuring Young's modulus, proportional limit, strain rate, and ultimate tensile stress of samples. The method of heating and proposed grip solutions must not cause any damage to the sample by chemical contamination of extraneous species, and must maintain uniform heating in the sample gauge section during testing. If Phase I does not include elevated temperature bench scale tests, thermal/structural FEA models should demonstrate structural margin in each of the test apparatus components when test sample stresses are up to 300 MPa at 3000 C. PHASE II: Demonstrate that the designed system in Phase I is capable of measuring Young's modulus, the proportional limit, strain rate, and ultimate tensile stress of samples at temperatures up to 3000 C. The designed system must be capable of measuring stresses up to 300 MPa at 3000 C. Proposers must obtain refractory material samples and test the samples at temperatures up to 3000 C; however, maximum stresses can be demonstrated by load capability of the test setup at temperature. PHASE III DUAL USE APPLICATIONS: Demonstrate scalability of the testing method to maximize the number of tests possible per day. The proposer must partner with a prime contractor or system manufacturers to test refractory materials for development projects. REFERENCES: Mechanical Properties of Wrought Tungsten. https://apps.dtic.mil/sti/citations/AD0427126 Tensile Strength of Carbon-Carbon Composites at High Temperature up to 2773K. Institute of physics https://iccm-central.org/Proceedings/ICCM17proceedings/papers/D3.6%20Kobayashi.pdf KEYWORDS: Testing; Tensile; Materials; High Temperature; Propulsion; Hypersonics