SBIR-STTR Award

Recent developments with the maturation and characterization of MAX phase materials indicate that a handful of these materials would be suitable for the heat produced by third stage rocket motors (TSRM). The majority of investigations have focused on alumina forming ‘211’ MAX phase systems that form an adherent oxide scale. However, tantalum carbide forming MAX phase materials offer an alternative approach to high performance rocket motor throat materials. As opposed to the expensive/difficult route of fabricating and machining bulk tantalum carbide, tantalum carbide forming MAX phase materials are readily machinable and thermally decompose into tantalum carbide at elevated temperatures. MR&D plans to team up with the Greenleaf Corporation in order to investigate a tantalum carbide forming MAX phase composition for TSRM throats. This proposed MAX phase material evaluation work will be accomplished with a three-pronged approach including computational thermomechanical analyses of the rocket motor throat supported by first-principle property prediction techniques, fabrication optimization techniques to produce a phase pure MAX phase composition, and material characterization via thermomechanical testing and oxyacetylene torch test evaluation. Approved for Public Release | 20-MDA-10643 (3 Dec

MAX phase materials are metallic ceramics known for combining favorable mechanical properties (such as good machinability and high elastic moduli) with good thermal shock resistance, low thermal expansion coefficients, and rigidity at elevated temperatures. In general, the MAX phases are a class of material consisting of a combination of three types of elements: M (an early transition metal), A (a group A element), and X (carbon and/or nitrogen). These materials are often referred to as ‘211’, ‘312’, ‘413’, etc., based on the amount of each element in the compound. Ta4AlC3, for instance, is considered a ‘413’ MAX phase material. The Missile Defense Agency (MDA) SBIR topic to which Materials Research & Design, Inc. (MR&D) is responding seeks innovative solutions for the development of structural MAX phase materials to improve the technology readiness levels of constituent technologies essential to a high capacity future interceptor. Specifically, the platforms of interest are second and third stage rocket motors, with the goal being to develop MAX phase materials which are able to withstand the mechanical and thermal stresses of terminal missile defense maneuvers. During MR&D’s Phase I program, a combined analytical and experimental proof-of-principle study was conducted to demonstrate the theoretical feasibility of using a tantalum-based MAX phase material – the so-called ‘413’ MAX phase, Ta4AlC3 – in solid propellant environments relevant to second and third stage rocket motors. This was accomplished through the successful synthesis of various Ta4AlC3 materials, XRD/EDS/SEM evaluations, elevated temperature thermomechanical characterization, and an extensive elastic-plastic finite element analysis to assess theoretical survivability under various conditions. Ultimately, MR&D found that the Ta4AlC3 MAX phase material showed feasibility as a candidate material in thermal shock environments over a wide range of conditions. The Phase II program will build on this work in several ways, ultimately culminating with prototype components being subjected to various solid propellant combustion environments. MR&D has enlisted the support of a cadre of subject matter experts from the materials field. The Phase II team will include Dr. Michel Barsoum of Drexel University, Greenleaf Corporation, Penn State University, Southern Research, Dr. William Carty of Alfred University, and Northrop Grumman (Elkton, MD). Approved for Public Release |