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Search Publications by: Maureen E. Williams (Fed)

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Displaying 26 - 50 of 106

Solidification of Ni-Re Peritectic Alloys

February 4, 2019
Author(s)
William J. Boettinger, Dale E. Newbury, Nicholas W. Ritchie, Maureen E. Williams, Ursula R. Kattner, Eric Lass, Kil-Won Moon, Michael B. Katz
Differential thermal analysis (DTA) and microstructural and microprobe measurements of DTA and as-cast Ni-Re alloys with compositions between 0.20 and 0.44 mass fraction Re provide information to resolve differences in previously published Ni-Re phase

Diffusion in the Ti-Al-V system

August 23, 2018
Author(s)
Greta Lindwall, Kil-Won Moon, Zhangqi Chen, Michael J. Mengason, Maureen E. Williams, Justin Gorham, Ji-Cheng Zhao, Carelyn E. Campbell
Diffusion in the Ti-Al-V system is studied and a CΑLPHAD diffusion mobility description is developed. Diffusion couple experiments are used to obtain information of Al and V diffusion in the α phase. This includes diffusion paths at the temperatures 923 K

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

Application of Finite Element, Phase-field, and CALPHAD-based Methods to Additive Manufacturing of Ni-based Superalloys

September 21, 2017
Author(s)
Trevor Keller, Greta Lindwall, Supriyo Ghosh, Li Ma, Brandon M. Lane, Fan Zhang, Ursula R. Kattner, Eric Lass, Yaakov S. Idell, Maureen E. Williams, Andrew J. Allen, Jonathan E. Guyer, Lyle E. Levine
Numerical simulations are used in this work to investigate aspects of microstructure and microsegregation during rapid solidification of a Ni-based superalloy in a laser powder bed fusion additive manufacturing process. Thermal modeling by finite element

Formation of the Ni3Nb delta-phase in stress-relieved Inconel 625 produced via powder-bed laser fusion additive manufacturing

August 23, 2017
Author(s)
Eric Lass, Mark R. Stoudt, Maureen E. Williams, Michael B. Katz, Thien Q. Phan, Lyle E. Levine, Thomas H. Gnaeupel-Herold
The microstructural evolution of laser powder-bed additively manufactured Inconel 625 during a post-build stress-relief anneal of 1 h at 870 °C is investigated. It is found that this industry-recommended heat treatment promotes the formation of a

Interdiffusion in the Ni-Re System: Evaluation of Uncertainties

June 23, 2017
Author(s)
William J. Boettinger, Maureen E. Williams, Kil-Won Moon
Diffusion couple experiments between Ni and Re at 1200°C and 1350°C were performed. These experiments established the limits of the two-phase FCC + HCP region. No intermediate phase was observed at these temperatures. Composition dependent interdiffusion

Homogenization Kinetics of a Nickel-based Superalloy Produced by Powder Bed Fusion Laser Sintering

January 26, 2017
Author(s)
Fan Zhang, Lyle E. Levine, Andrew J. Allen, Eric Lass, Sudha Cheruvathur, Mark R. Stoudt, Maureen E. Williams, Yaakov S. Idell, Carelyn E. Campbell
Additively manufactured (AM) metal components often exhibit fine dendritic microstructures and elemental segregation due to the initial rapid solidification and subsequent melting and cooling during the build process, which without homogenization would

Diffusion in FCC Co-Al-W Alloys at 900 degree C and 1000 degree C

August 17, 2016
Author(s)
Kil-Won Moon, Carelyn E. Campbell, Maureen E. Williams, William J. Boettinger
Diffusion couple experiments between various Co-rich face centered cubic alloys in the Co-W-Al ternary system have been conducted at 900 degree C and 1000 degree C. Diffusion coefficients have been extracted for the Co-W binary and for ternary alloys at