LEAPS-MPS: In-Situ Gas Alloying for Nano Synthesis and Dispersion in Metallic Matrices

About This Grant

NON-TECHNICAL SUMMARY This research project explores a novel approach to creating stronger, more heat- and stress-resistant metals for extreme environments, including space, nuclear reactors, and advanced energy systems. A traditional method for strengthening metals rely on mixing in tiny particles that often degrade under harsh conditions. This project is developing an innovative technique that forms these particles during 3D printing itself, using reactive gases such as nitrogen and oxygen. These gases are injected into a pool of molten metal and chemically react to form durable ceramic particles inside the metal as it solidifies. The project is utilizing a process called Directed Energy Deposition, a type of additive manufacturing, to conduct this gas-metal reaction while printing parts layer by layer. This eliminates the need for expensive and energy-intensive pre-processing steps, such as mechanical alloying. The result is a more efficient and scalable method for producing metal components that are stronger, more durable, and suitable for extreme applications. The work supports national priorities in energy, defense, and manufacturing by reducing production costs and enabling the development of new high-performance materials. It also contributes to building a skilled STEM workforce. Each year, the project is engaging college and high school students in hands-on research at the University of Texas Rio Grande Valley. Outreach programs include dual-credit courses, K-12 STEM workshops, and public events that highlight how advanced manufacturing connects to real-world challenges. This project is helping expand UTRGV’s research capacity and supports the goal of furthering scientific exploration and opportunity throughout the nation. TECHNICAL SUMMARY This research project investigates in-situ gas-phase alloying during Directed Energy Deposition (DED) as a scalable, energy-efficient method for synthesizing and dispersing nanoscale strengthening phases within metallic matrices such as stainless steel 316 and aluminum-silicon alloys. Instead of relying on conventional dispersion-strengthening methods, such as mechanical alloying, this approach introduces reactive gases, such as nitrogen and oxygen, directly into the laser-induced melt pool. These gases react under far-from-equilibrium solidification conditions to form ceramic nanoparticles that enhance the mechanical and thermal performance of the resulting materials. The project pursues three integrated research objectives: (1) model and validate gas-metal reactions and nanoparticle nucleation using thermodynamic, kinetic, and computational fluid dynamics tools; (2) characterize the dispersion, size, and morphology of nanoparticles using transmission electron microscopy, scanning transmission electron microscopy with energy-dispersive spectroscopy, and electron backscatter diffraction; and (3) correlate nanoparticle features with mechanical properties such as hardness and grain size using structure-property-process modeling and nanoindentation testing. A semi-empirical framework will relate gas partial pressure, thermal gradients, and melt flow dynamics, including Marangoni convection and turbulence, to nanoparticle formation and distribution. This research is is seeking to demonstrate an improvement of more than 20 percent in hardness, refined grain structures with diameters below 10 microns, and uniform nanoparticle dispersions. Educational impacts include integration into undergraduate and graduate coursework, dual-credit high school classes, K–12 workshops, and community seminars. The outcomes support NSF’s goals in advancing materials research and manufacturing technologies, while promoting STEM workforce development, and supporting UTRGV’s goal of contributing to cutting edge science in support of national interests. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.