Development of Steel Powder for High-Strength and Damage-Tolerant AM parts

Additive Manufacturing (AM) of metallic components has evolved from prototyping to industrial-scale production, enabling the fabrication of complex geometries for high-performance applications. Laser-Beam Powder Bed Fusion (LB-PBF) and Electron-Beam Powder Bed Fusion (EB-PBF) are among the most established AM techniques, which currently rely on conventional materials. However, limited knowledge exists on the additive manufacturing of advanced steels such as duplex, oxide dispersion-strengthened (ODS), and Transformation-/Twinning-Induced Plasticity (TRIP/TWIP) steels. This highlights the need for developing novel steel alloys specifically tailored for AM, as the final properties of printed parts are strongly influenced by the feedstock composition. This study focuses on optimizing X15CrMnNiN15-3-3-0.15, a high-strength, metastable austenitic TRIP/TWIP steel alloy, produced via the crucible-free Electrode Inert Gas Atomization (EIGA) process. The EIGA process minimizes manganese evaporation and de-nitriding, critical for preserving the powder’s designed composition. Efforts to minimize energy and argon consumption during atomization further enhance process sustainability. Two critical process variables—electrode melting rate and atomization gas preheating—were varied to investigate their effects on powder characteristics, including particle size distribution (PSD), morphology, flowability, bulk density, magnetic saturation, and microstructure. Optimization of these parameters resulted in a refined PSD (lower D50) and highly spherical powders with minimal porosity and satellite formation, primarily consisting of the austenitic phase, enhancing suitability for both LB-PBF and EB-PBF applications. While this work focuses on powder development, future efforts will involve the use of these powders in AM to fabricate test components. These components will then be subjected to Quenching and Partitioning (Q&P) heat treatment, with the aim of achieving a tempered martensitic structure that enhances damage tolerance. The initial findings suggest promising potential for an alloy concept with improved processability, isotropic microstructures, and enhanced mechanical properties, which could contribute to the development of high-performance AM components with improved reliability, damage tolerance, and operational efficiency, for future industrial and medical applications.