N13A-T012 TITLE: Mechanical Property Characterization and Modeling for Structural Mo-Si-B Alloys for High Temperature Applications

TECHNOLOGY AREAS: Air Platform, Materials/Processes

ACQUISITION PROGRAM: EPE FY08-08

OBJECTIVE: Develop and mature mechanical property models that will predict mechanical properties of refractory alloys. Development of similar predictive tools to support screening of refractory alloys and optimization of chemistry and microstructure will enable near-term implementation of this class of structural materials.

DESCRIPTION: There is a need to develop mechanical property models and associated engineering codes for the prediction of mechanical properties of refractory alloys. Models and simulation codes have been established for nickel-based superalloys. Development of similar predictive tools to support screening of refractory alloys and optimization of chemistry and microstructure will enable near-term implementation of this class of structural materials.

Characterization of the powder chemistry and interstitials should be document during each stage of the processing. Following development of a specific process to produce medium scale material lots of Mo-Si-B powder, maturation of the parameters required to perform a small scale Mo-Si-B extrusion is also required. Characterization of the extruded material properties should be performed. Ideally this characterization would include measurement of the tensile properties up to 2300 degrees F and potentially 2500 degrees F, as well as the creep resistance of the alloy at 2000 degrees F or higher. This characterization should also include documentation of the static oxidation resistance at three or four key temperatures across a range between 1500F to 2500 degrees F.

PHASE I: Given a specific processing path for a Mo-Si-B alloy, one will characterize the room temperature mechanical properties of the refractory alloy (ultimate, yield, compressive, fatigue, etc.) in small parts. . Design plans for material mechanical property characterization at several high temperatures ranging from 1500F to 2500 degrees F. Microstructures need to be recorded and correlated with all mechanical property measurements. ICME (integrated computational materials engineering) should be utilized to assist in development of a material/process/property relationship.

PHASE II: Mechanical characterization of Mo-Si-B alloy samples at several high temperatures ranging from 1500F to 2500 degrees F. Conduct material property tests at the level required to provide data for the design of a suitable component for an OEM for relevant engine components. Using ICME, provide material for manufacture and test of the suitable component.

PHASE III: Transition the material characterization and models to a suitable industrial material producer or engine OEM (original engine manufacturer). Commercialize the material for use in DoD and civilian markets.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: If these models are successfully developed, the material would have utility as high temperature material of construction for civil air transport and as a high temperature forging die material for both commercial and military production equipment.

REFERENCES:
1. R.L. Fleischer. "High Temperature, High Strength Materials - an Overview, Journal of Metals 37(12) 16-20, 1985.

2. J.D. Destefani, Advances in Intermetallics, Advanced Materials and Processes, 135 (2) 37-41, 1989.

3. J.H. Schneibel, et al. Assessment of processing routes and strength of a 3-phase molybdenum boron silicide, Scripta Materialia, 38(7) 1169-1176, 1998.