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Search Publications by: Mark R. Stoudt (Fed)

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Displaying 1 - 25 of 70

Effect of austenite fraction and stability on strength-hardening-ductility in additively manufactured 17-4 PH stainless steel containing nitrogen

June 30, 2023
Author(s)
Saadi Habib, Steven P. Mates, Fan Zhang, Mark R. Stoudt, James Zuback, Olaf Borkiewicz
Additively-manufactured (AM) 17-4 precipitation-hardening (PH) martensitic stainless steel (SS) built from nitrogen-atomized powder often retains a large volume fraction of austenite. The retained austenite lowers the yield strength compared to both

Developing an Appropriate Heat Treatment Protocol for Additively Manufactured Alloy 718 for Oil and Gas Applications

March 23, 2023
Author(s)
Mark R. Stoudt, James Zuback, Carelyn E. Campbell, Maureen E. Williams, Kil-Won Moon, Carlos R. Beauchamp, Mark Yunovich
The combination of strength, corrosion resistance, and excellent weldability makes Alloy 718 an attractive alloy for additive manufacturing (AM) applications, but the AM build process generates considerable residual stresses, and large compositional and

How Austenitic is a Martensitic Steel Produced by Laser Powder Bed Fusion? A Cautionary Tale

December 2, 2021
Author(s)
Fan Zhang, Mark R. Stoudt, Souzan Hammadi, Carelyn E. Campbell, Eric A. Lass, Maureen E. Williams
Accurate phase fraction analysis is an essential element of microstructural characterization of alloys and often serves as a basis to quantify effects such as heat treatment or mechanical deformation. Additive manufacturing (AM) of metals, due to the

Solid-State Transformation of an Additive Manufactured Inconel 625 Alloy at 700 degC

September 23, 2021
Author(s)
Fan Zhang, Jan Ilavsky, Greta Lindwall, Mark R. Stoudt, Lyle E. Levine, Andrew J. Allen
Inconel 625, a nickel-based superalloy, has drawn much attention in the emerging field of additive manufacturing (AM) because of its excellent weldability and resistance to hot cracking. The extreme processing condition of AM often introduces enormous

Additive Manufacturing of Steels and Stainless Steels

August 1, 2020
Author(s)
Carelyn E. Campbell, Mark R. Stoudt, Fan Zhang
This work briefly reviews the classification of the different types of steels, the most common AM processes used for steel and the available powder feedstock. The characteristics of the as-built microstructure, including porosity, inclusions and residual

Location-specific Microstructure Characterization Within IN625 Additive Manufacturing Benchmark Test Artifacts

March 3, 2020
Author(s)
Mark R. Stoudt, Maureen E. Williams, Lyle E. Levine, Adam Abel Creuziger, Sandra A. Young, Jarred C. Heigel, Brandon Lane, Thien Q. Phan
Additive manufacturing (AM) of metals creates segregated microstructures with significant differences from those of traditional wrought alloys. Understanding how the local build conditions generate specific microstructures is essential for developing post

Outcomes and Conclusions from the 2018 AM-Bench Measurements, Challenge Problems, Modeling Submissions, and Conference

February 13, 2020
Author(s)
Lyle E. Levine, Brandon M. Lane, Jarred C. Heigel, Kalman D. Migler, Mark R. Stoudt, Thien Q. Phan, Richard E. Ricker, Maria Strantza, Michael R. Hill, Fan Zhang, Jonathan E. Seppala, Edward J. Garboczi, Erich D. Bain, Daniel Cole, Andrew J. Allen, Jason C. Fox, Carelyn E. Campbell
The Additive Manufacturing Benchmark Test Series (AM-Bench) was established to provide rigorous measurement test data for validating additive manufacturing (AM) simulations for a broad range of AM technologies and material systems. AM-Bench includes

Measurements of Melt Pool Geometry and Cooling Rates of Individual Laser Traces on IN625 Bare Plates

February 5, 2020
Author(s)
Brandon M. Lane, Jarred C. Heigel, Richard E. Ricker, Ivan Zhirnov, Vladimir Khromchenko, Jordan S. Weaver, Thien Q. Phan, Mark R. Stoudt, Sergey Mekhontsev, Lyle E. Levine
The complex physical nature of the laser powder bed fusion (LPBF) process warrants use of multiphysics computational simulations to predict or design optimal operating parameters or resultant part qualities such as microstructure or defect concentration

Phase Fraction and Evolution of Additively Manufactured 15-5 Stainless Steel and Inconel 625 AM- Benchmark Artifacts

August 5, 2019
Author(s)
Fan Zhang, Lyle E. Levine, Andrew J. Allen, Sandra A. Young, Maureen E. Williams, Mark R. Stoudt, Kil-Won Moon, Jarred C. Heigel, Jan Ilavsky
A proper understanding of the structure and microstructure of additive manufactured (AM) alloys is essential not only to the prediction and assessment of their material properties, but also to the validation and verification of computer models essential to

Simulation of TTT curves for additively manufactured Inconel 625

January 1, 2019
Author(s)
Carelyn E. Campbell, Greta Lindwall, Eric Lass, Fan Zhang, Mark R. Stoudt, Andrew J. Allen, Lyle E. Levine
The ability to use common computational thermodynamic and kinetic tools to study the microstructure evolution in Inconel 625 (IN625) manufactured using the additive manufacturing (AM) technique of laser powder-bed fusion is evaluated. Solidification

The Effects of Laser Powder Bed Fusion Process Parameters on Material Hardness and Density for Nickel Alloy 625

August 21, 2018
Author(s)
Christopher U. Brown, Gregor Jacob, Antonio M. Possolo, Carlos R. Beauchamp, Max A. Peltz, Mark R. Stoudt, M A. Donmez
The goal of this study was to investigate the relationship between mechanical and material properties (including density) of manufactured nickel super alloy (IN625) using a laser powder bed fusion process and three process parameters: laser power, hatch

Systems Design Approach to Low-Cost Coinage Materials

June 20, 2018
Author(s)
Eric Lass, Mark R. Stoudt, Carelyn E. Campbell
A system design approach using an Integrated Computational Materials Engineering (ICME) was used to design three new low-cost seamless replacement coinage alloys to reduce the raw material of the current US coinage alloys. Maintaining compatibility with

Effect of Heat Treatment on the Microstructural Evolution of a Nickel-Based Superalloy Additive-Manufactured by Powder Bed Fusion Laser Sintering

June 15, 2018
Author(s)
Fan Zhang, Lyle E. Levine, Andrew J. Allen, Mark R. Stoudt, Greta Lindwall, Eric Lass, Maureen E. Williams, Yaakov S. Idell, Carelyn E. Campbell
Elemental segregation is a ubiquitous phenomenon in additive-manufactured (AM) parts due to solute rejection and redistribution during the rapid solidification process. Using electron microscopy, in situ synchrotron X-ray scattering and diffraction, and

The Influence of Annealing Temperature and Time on the Formation of delta-Phase in Additively-Manufactured Inconel 625

May 10, 2018
Author(s)
Mark R. Stoudt, Eric Lass, Daniel S. Ng, Maureen E. Williams, Fan Zhang, Carelyn E. Campbell, Greta Lindwall, Lyle E. Levine
This research evaluated the kinetics of delta-phase growth in laser powder bed additively- manufactured (AM) Inconel 625 during post-build stress-relief heat treatments. The temperatures ranged between 650 °C to 1050 °C, and the times from 0.25 h to 168 h

Formation of Nb-rich droplets in laser deposited Ni-matrix microstructures

March 15, 2018
Author(s)
Supriyo Ghosh, Mark R. Stoudt, Lyle E. Levine, Jonathan E. Guyer
Ni-rich $\gamma$ cells/dendrites and Nb-rich eutectic droplets that form during laser power bed fusion (LPBF) solidification of Ni-Nb alloys are studied in the present work using numerical simulations. Finite element simulations estimate the local cooling

Single Track Melt Pool Measurements and Microstructures in Inconel 625

February 20, 2018
Author(s)
Supriyo Ghosh, Li Ma, Lyle E. Levine, Richard E. Ricker, Mark R. Stoudt, Jarred C. Heigel, Jonathan E. Guyer
We use single track laser melting experiments and simulations on Inconel 625 to estimate the dimensions and microstructures of the resulting melt pools. Our work is based on a design-of- experiments approach which uses multiple laser power and scan speed
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