Recent Ph.D. alumni Matthew Swenson published some of the results from his doctoral research in the Journal of Nuclear Materials. The article summarizes the irradiation-induced oxide nanocluster evolution in a model Fe-9%Cr oxide dispersion strengthened (ODS) steel, as well as the G-phase (Si, Ni, Mn-rich phase) nanocluster evolution in the HT9 and HCM12A commercial ferritic/martensitic (F/M) alloys. The article presents atom probe tomographic (APT) results, and studies these results in the context of previous APT investigations of the same alloy heats. Collectively, studying the results in this broader context enable us to draw conclusions about the separate influences of irradiation dose rate and particle type on the nanocluster evolution. The paper concludes by suggesting that a negative temperature shift may be necessary in order for higher dose rate irradiations to properly emulate the nanocluster evolution from lower dose rate irradiations. Congratulations on publishing this work, Matthew!
The full citation is:
M.J. Swenson and J.P. Wharry. Nanocluster irradiation evolution in Fe-9%Cr ODS and ferritic-martensitic alloys. Journal of Nuclear Materials 496 (2017) 24-40. doi: 10.1016/j.jnucmat.2017.08.045
Janelle Wharry recently presented seminars at the School of Materials Engineering at Purdue University and at Oak Ridge National Laboratory. The Purdue MSE seminar focused on the group’s development of TEM in situ mechanical testing techniques for irradiated materials, led by students Kayla Yano and Priyam Patki. The ORNL seminar focused on the irradiation evolution of nanoclusters in oxide dispersion strengthened (ODS) and ferritic/martensitic (F/M) steels. Janelle presented the group’s experimental results obtained by atom probe tomography, and the subsequent predictive capabilities developed by Matthew Swenson and coded by Didier Ishimwe.
The ORNL seminar was part of the ORAU Travel Grant program. Thank you to Dr. Kevin Field for hosting!
Kayla Yano presented an invited seminar at Oak Ridge National Laboratory (ORNL). Her seminar was entitled In Situ TEM & Fe-9%Cr ODS, and focused on exploring a wide variety of transmission electron microscopic (TEM) in situ mechanical testing configurations, specifically as applied to an Fe-9%Cr oxide dispersion strengthened (ODS) alloy.
Kayla received the invitation to this seminar, along with research meetings and tours of ORNL, as part of her American Nuclear Society best poster award. Congratulations again, Kayla!
Ph.D. student Keyou Mao presented his research on microstructural and micromechanical characterization of a 304 stainless steel laser weldment at the Microscopy & Microanalysis 2017 Meeting in St. Louis, Missouri. Janelle Wharry also presented an invited talk overviewing in situ TEM fracture testing of irradiated materials. Thank you, Dr. Sanjit Bhowmick (Bruker), for the invitation!
Conference proceedings are archived as follows:
- K. Mao, Y.Q. Wu, and J.P. Wharry. EBSD and TEM analysis of the heat affected zone of laser welded AISI 304/308 stainless steel. Microscopy & Microanalysis, 23.S1 (2017) 2212.
- J.P. Wharry and K.H. Yano. In situ TEM fracture testing for shallow ion irradiated layers. Microscopy & Microanalysis, 23.S1 (2017) 738.
Janelle Wharry has received a travel grant from Oak Ridge Associated Universities, to support student training and development of collaborations with researchers at Oak Ridge National Laboratory. She will use the grant to share our recent research results, visit the LAMBDA facility, and strengthen relationships for future collaborative proposals.
Our undergraduate summer researchers have come to the end of a productive summer research experience. They had the opportunity to showcase their research outcomes at two different undergraduate research symposia on campus. Esteban Bautista and Didier Ishimwe presented their posters at the Network for Computational Nanotechnology Undergraduate Research Symposium. Didier presented his poster again, and Alex Bullens presented his poster, at the College of Engineering Summer Undergraduate Research Fellowship (SURF) Symposium.
The citations are:
- D. Ishimwe, M. Swenson, J.P. Wharry. Irradiation-induced nanocluster evolution. Purdue University Network for Computational Nanotechnology (NCN) Summer Undergraduate Research Fellowship (SURF) Symposium, West Lafayette IN, 2017.
- E. Bautista, A. Bullens, J.P. Wharry. Understanding the role of fabrication method on metal alloys used in nuclear power plants. Purdue University Network for Computational Nanotechnology (NCN) Summer Undergraduate Research Fellowship (SURF) Symposium, West Lafayette IN, 2017.
- A. Bullens, E. Bautista, K. Mao, J.P. Wharry. Comparison of PM-HIP to cast Alloy 625 for nuclear applications. Purdue University College of Engineering Summer Undergraduate Research Fellowship (SURF) Symposium, West Lafayette IN, 2017.
Janelle Wharry delivered an invited seminar at the Instituto de Investigación en Metalurgia y Materiales (Metals & Materials Research Institute), at the Universidad Michoacana de San Nicolás de Hidalgo, in Morelia, Mexico. Her seminar was part of a metals and materials workshop hosted in celebration of the Institute’s 45th anniversary and the University’s 100th anniversary. Janelle’s talk focused on using TEM in situ mechanical testing to gain a deeper understanding of deformation mechanism in irradiated alloys. Janelle also gave a second talk about graduate opportunities at Purdue for international students.
Thank you, Dr. Alberto Ruiz Marines, for the invitation and your hospitality! Morelia and neighboring town Patzcuaro were beautiful — please enjoy some photos below.
The full citation of the technical talk is:
J.P. Wharry. Understanding deformation mechanics of ion irradiated alloys by TEM in situ testing. Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, Institute’s 45th Anniversary & University’s 100th Anniversary Celebration, Morelia, Mexico, June 2017.
Our group recently delivered two oral presentations at the American Nuclear Society 2017 Annual Meeting in San Francisco, CA. Both presentations were in a session focused on research output from the DOE Nuclear Science User Facilities.
The full citations for the talks are:
- K.H. Yano, P.V. Patki, M.J. Swenson, and J.P. Wharry. Correlation between irradiation defects and transition dimension for TEM in situ mechanical testing. American Nuclear Society 2017 Annual Meeting, San Francisco CA, June 2017.
- D.P. Guillen, J.P. Wharry, and D.W. Gandy. Ongoing irradiations of nuclear structural materials fabricated by powder metallurgy with hot isostatic pressing. American Nuclear Society 2017 Annual Meeting, San Francisco CA, June 2017.
Five new summer undergraduate researchers have joined the group for the summer. We are so excited to host them and provide them with some of their first research experiences. The students are:
Esteban Bautista – Pasadena City College
Alex Bullens – Senior, Purdue University
Sophia Chun – Freshman, University of Hawai`i
Esteban, Alex, and Sophia are working together to study the effects of thermal annealing on the grain size and hardness of structural alloys fabricated by casting/forging compared to powder metallurgy with hot isostatic pressing (PM/HIP). Esteban joins us through Purdue’s Network for Computation Nanotechnology SURF Program, Alex is participating in Purdue’s College of Engineering SURF Program, and Sophia joins us having participated in the Kamehameha Schools-University of Hawai`i Science Fair Program.
Didier Ishimwe – Junior, William Penn University
Didier is studying Computer Science, and is participating in Purdue’s Network for Computational Nanotechnology SURF Program. Didier is building a computational tool to predict irradiation evolution of embedded nanoclusters. The tool will be made available on nanoHUB.
Hernan Lopez – Senior, Cal Poly Pomona
Hernan is studying Mechanical Engineering, and has previous research experience in mechanical properties and corrosion. Hernan is conducting finite element analyses to complement our ongoing transmission electron microscopic (TEM) in situ mechanical testing efforts. Hernan joins us having participated in Purdue’s Pathways to the Professoriate Program.
Welcome to Purdue and West Lafayette!