Very Efficient Nozzle Materials (VENoM)

Very Efficient Nozzle Materials (VENoM) Modern solid rocket motors (SRMs) use advanced propellant formulations that produce increasingly high temperatures and pressures in anticipation of improved performance. These extreme environments can lead to SRM nozzle degradation, deposits of unwanted material, and ultimately nozzle failure. Innovative materials are crucial for SRM nozzles to survive in extreme thermal and oxidative environments, and producing said nozzle materials at a relatively low cost is necessary for common and sustained implementation. In this Phase I effort, called Very Efficient Nozzle Materials (VENoM), novel ultra-high temperature alloys exhibiting a balance of strength, oxidation and erosion resistance, thermal shock resistance, and manufacturability will be developed. This will be accomplished via an Integrated Computational Materials Engineering program that utilizes (1) simulations of rocket nozzle behavior under flight conditions, (2) a combination of high-throughput computational modeling and machine learning to rapidly explore, design, and select new alloys, and (3) rapid alloy fabrication and small-scale testing for feedback into (1) and (2). The materials design strategy must consider alloys that melt above approximately 2800║C, which means that the alloy design space significantly shrinks to individual alloying elements that melt above around 2000║C. Thus, the Phase I focus will center around the W-Ta-Nb-Mo-Hf-Ir-Re system with or without the additions of a fine dispersion of carbides or oxides to enhance strength. This system was selected because the range of elements provides sufficiently disparate atomic radii to enhance the intrinsic strength of body-centered cubic structures that are likely to form, and the additions of Hf and to some extent Ir and Re will likely improve oxidation/erosion resistance through the formation of HfO2 oxides. These materials and components will be fabricated via a directed energy deposition process and tested using commercially available small solid rocket motors. Approved for Public Release | 24-MDA-11906 (16 Sep 24)