2023 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2023): Particulate and Dispersoid Reinforced Metals
Program Organizers: Joseph Beaman, University of Texas at Austin
Wednesday 3:20 PM
August 16, 2023
Room: 416 AB
Location: Hilton Austin
Session Chair: Jared Allison, University of Texas Austin
3:20 PM
Effect of Solidification Conditions on the Evolution of Dispersoids in a Ni-20Cr + 1 wt% Y2O3 ODS Alloy Fabricated with Laser Powder Bed Fusion: Nathan Wassermann1; Alan McGaughey1; Sneha Narra1; 1Carnegie Mellon University
Oxide dispersion strengthened (ODS) alloys contain a high number density of nano-scale oxide dispersoids, offering exceptional high-temperature creep strength. Though these alloys offer a range of desirable properties, existing manufacturing methods are inconsistent, costly, and often yield anisotropic microstructures. While ODS alloys have been researched in the additive manufacturing (AM) literature, the evolution of nano-oxide dispersoids during AM processing is not well-understood. In this investigation, laser powder bed fusion (L-PBF) is used to fabricate samples of a Ni-20Cr + 1 wt% Y2O3 ODS alloy. A range of power-velocity combinations are applied, and differences in the evolution of nano-oxide dispersoids are evaluated across the processing space. Results from a heat transfer model are integrated with a model for inclusion growth, which is connected to the microstructure of the fabricated samples. The results of this investigation contribute to AM process design for ODS alloys.
3:40 PM
Oxide Dispersion Strengthened (ODS) SS316L Prepared by Laser Powder Bed Fusion: Analysis of Microstructure and Hardness Properties: Changyu Ma1; Yu-Keng Lin2; Tianqi Zheng2; Philip Mallory3; Y. Morris Wang2; Xiaochun Li2; Bruce Kang3; Bingbing Li1; 1California State University Northridge; 2University of California Los Angeles; 3West Virginia University
Dense oxide dispersion strengthened (ODS) SS316L with 0.5wt.% Y2O3 fabricated by laser powder bed fusion (L-PBF) additive manufacturing using spherical SS316L powder embedded with nano-Y2O3 and different building patterns. The density, grain growth, phase formation, and microhardness of the as-printed ODS SS316L were investigated through optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-Ray Spectroscopy (EDX), and Vickers hardness testing, respectively. The results showed that there was uniform dispersion of Y-rich nanoparticles in dense ODS SS316L printed with meander and chessboard patterns owing to the ultrafine Y2O3 in powder feedstock, contributing to a fine-grain structure in the as-printed ODS SS316L. A smaller molten pool was observed in ODS SS316L printed with a chessboard pattern compared to meander strategy, and enhanced microhardness was observed in ODS SS316L compared to pristine SS316L. Based on the above findings, the Y2O3 effects on microstructure evolution and reinforcing mechanisms of microhardness were discussed.
4:00 PM
Influence of TiC-Nanoparticles on the Material Properties of AlSi10Mg Manufactured by Laser Powder Bed Fusion: Victor Lubkowitz1; Torsten Scherer2; Frederik Zanger1; Volker Schulze1; 1wbk Institute of Production Science, Karlsruhe Institute of Technology (KIT); 2INT Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT)
Additive manufacturing enables the production of complex lightweight components. However, the poor usage of atomized metal powders is a challenge, as fine particles must be removed from the powder feedstock to ensure flowability. Further new high strength aluminum alloys are needed. Some investigations show that the mechanical properties of AlSi10Mg can be improved by adding TiC nanoparticles. The aim of this study is to determine if the influence of small amounts of TiC additions, which are normally used to improve the flowability of fine powders, is also sufficient to improve the mechanical properties. It was found that the addition of 0.46 wt% TiC-Nanoparticles with a size of 50 nm led to a homogeneous grain size distribution and an increase of 16 % in yield strength compared with pure AlSi10Mg. Further a strong median grain size reduction from 5.08 to 2.74 µm could be observed by adding 0.96 wt% of TiC-Nanoparticles.
4:20 PM
Process Structure Relationships of Carbide Containing Molybdenum Alloys Produced via Electron Beam Powder Bed Fusion: Christopher Ledford1; Patxi Fernandez-Zelaia1; Michael Kirka1; 1Oak Ridge National Laboratory
Recent success in the processing of refractory materials using additive manufacturing shows the viability of using these techniques to process more complex refractory alloys. Carbide containing molybdenum alloys exhibit good high temperature properties but are difficult to traditionally manufacture. Here we show the use of electron beam powder bed fusion to fabricate highly dense crack free material of two different carbide containing molybdenum alloys (Mo-TiC and MoReHfC). Process structure relationships are explored for each alloy along with effect of heat treatments on those properties.