Session: 17-01-01: Research Posters

Paper Number: 147102

147102 - Multi-Scale Modeling and Experimental Analysis of 0.8 Wt% Y2o3-Strengthened Ss316l Ods Alloys Fabricated via Lpbf 

Oxide Dispersion Strengthened (ODS) stainless steel alloys are renowned for their exceptional performance in harsh and high-temperature conditions, making them invaluable for applications in energy, aerospace, and other advanced engineering fields. The addition of oxide nanoparticles significantly enhances the mechanical properties and thermal stability of stainless steel (SS), providing superior creep resistance, strength, and oxidation resistance at elevated temperatures. Despite these advantages, traditional production techniques for ODS materials are limited by several significant challenges, including geometric constraints, difficulties in fabricating large-scale components, and high costs associated with multiple, complex solid-state processing stages. These stages increase production time, energy consumption, and overall costs, making the production of ODS alloys less economically viable. This research aims to overcome these limitations by introducing novel methods involving ex-situ preparation via ball-milling for Laser Powder Bed Fusion (LPBF). The use of additive manufacturing techniques, particularly LPBF, offers the potential for near-net-shape production of ODS alloys with intricate geometries and tailored microstructures, significantly enhancing their applicability in high-performance engineering sectors.

 

This study focuses on evaluating the influence of submicron yttrium oxide on the microstructure of SS316L in ODS nanocomposites, fabricated using LPBF. A mixture of SS316L and 0.8wt% Y₂O₃ powder was used, prepared via ball-milling to ensure a homogeneous distribution of yttrium oxide nanoparticles. The LPBF experiments were conducted with laser powers of 110 W and 220 W and scan speeds of 150, 300, 600, and 900 mm/s at a layer thickness of 40 microns. The optimal condition was found to be 110 W and 300 mm/s, based on density measurements and cross-sectional view observations of defect-free samples. Microstructural analysis revealed a uniform distribution of Y-O nanoparticles within the LPBF SS316L matrix, indicating successful incorporation and dispersion of the oxide particles. The particle size distribution and chemical composition analysis were conducted via scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS).

 

A multi-scale model was established to predict the size distribution of nanoparticles in ODS SS316L samples with varying process parameters, such as laser power and scanning speed. The temperature profile and cooling rate during the LPBF process were calculated using a Computational Fluid Dynamics (CFD) model. The diffusivities of yttrium (Y) and oxygen (O), along with the binding energies of Y-O clusters in molten SS316L, were computed using Density Functional Theory (DFT) simulations. These results were then employed in a Cluster Dynamics (CD) model, based on diffusion-reaction rate theory, to predict the nanoparticle size distribution in as-built LPBF ODS SS316L samples. The modeling predictions showed good agreement with the experimental data across all LPBF conditions, validating the effectiveness of the modeling approach for predicting particle size characteristics in ODS SS316L alloys during the LPBF process.

Presenting Author: Seongun Yang Oregon State University

Presenting Author Biography: Seongun Yang is a highly regarded aerospace engineer and a doctoral candidate in Mechanical Engineering, specializing in Advanced Additive Manufacturing. He is currently focused on researching ODS alloy development using Laser Directed Energy Deposition and Laser Powder Bed Fusion, with a particular emphasis on the potential applications of metal additive manufacturing in Energy and Aerospace industries. Yang has significant prior experience working with the Aero Technology Research Institute of the Republic of Korea Air Force, where he honed his skills in Aircraft Structural Damage Assessment and developed pioneering hybrid repair techniques that blend Composite with Additive Manufacturing Materials. His unwavering dedication to the field promises to revolutionize metal additive manufacturing and its impact on the aerospace industry.

Authors:

Seongun Yang Oregon State University
Zhengming Wang Oregon State University
Kwangtae Son Oregon State University
Donghua Xu Oregon State University
Marc Albert Electric Power Research Institute
Somayeh Pasebani Oregon State University