Ramprashad Prabhakaran

Profile Information
Name
Mr. Ramprashad Prabhakaran
Institution
Pacific Northwest National Laboratory
Position
Scientist
Affiliation
Pacific Northwest National Laboratory
h-Index
ORCID
0000-0002-8117-2677
Expertise
Advanced Fuels, Friction Stir Welding, Fuel Cladding, Irradiation Damage Behavior, Mechanical Properties, Small-Scale Mechanical Testing
Publications:
"Ion irradiation and examination of Additive friction stir deposited 316 stainless steel" Priyanka Agrawal, Ching-Heng Shiau, Aishani Sharma, Zhihan Hu, Megha Dubey, Yu Lu, Lin Shao, Ramprashad Prabhakaran, Yaqiao Wu, Rajiv Mishra, Materials & Design Vol. 238 2024 112730 Link
This study explored solid-state additive friction stir deposition (AFSD) as a modular manufacturing technology, with the aim of enabling a more rapid and streamlined on-site fabrication process for large meter-scale nuclear structural components with fully dense parts. Austenitic 316 stainless steel (SS) is an excellent candidate to demonstrate AFSD, as it is a commonly-used structural material for nuclear applications. The microstructural evolution and concomitant changes in mechanical properties after 5 MeV Fe++ ion irradiation were studied comprehensively via transmission electron microscopy and nanoindentation. AFSD-processed 316 SS led to a fine-grained and ultrafine-grained microstructure that resulted in a simultaneous increase in strength, ductility, toughness, irradiation resistance, and corrosion resistance. The AFSD samples did not exhibit voids even at 100 dpa dose at 600 °C. The enhanced radiation tolerance as compared to conventional SS was reasoned to be due to the high density of grain boundaries that act as irradiation-induced defect sinks.
"Thermomechanical Properties of Neutron Irradiated Al3Hf-Al Thermal Neutron Absorber Materials" Donna Guillen, Mychailo Toloczko, Ramprashad Prabhakaran, Yuanyuan Zhu, Yu Lu, Yaqiao Wu, Materials Vol. 16 2023 5518 Link
thermal neutron absorber material composed of Al3Hf particles in an aluminum matrix is under development for the Advanced Test Reactor. This metal matrix composite was fabricated via hot pressing of high-purity aluminum and micrometer-size Al3Hf powders at volume fractions of 20.0, 28.4, and 36.5%. Room temperature tensile and hardness testing of unirradiated specimens revealed a linear relationship between volume fraction and strength, while the tensile data showed a strong decrease in elongation between the 20 and 36.5% volume fraction materials. Tensile tests conducted at 200 °C on unirradiated material revealed similar trends. Evaluations were then conducted on specimens irradiated at 66 to 75 °C to four dose levels ranging from approximately 1 to 4 dpa. Tensile properties exhibited the typical increase in strength and decrease in ductility with dose that are common for metallic materials irradiated at ≤0.4Tm. Hardness also increased with neutron dose. The difference in strength between the three different volume fraction materials was roughly constant as the dose increased. Nanoindentation measurements of Al3Hf particles in the 28.4 vol% material showed the expected trend of increased hardness with irradiation dose. Transmission electron microscopy revealed oxygen at the interface between the Al3Hf particles and aluminum matrix in the irradiated material. Scanning electron microscopy of the exterior surface of tensile tested specimens revealed that deformation of the material occurs via plastic deformation of the Al matrix, cracking of the Al3Hf particles, and to a lesser extent, tearing of the matrix away from the particles. The fracture surface of an irradiated 28.4 vol% specimen showed failure by brittle fracture in the particles and ductile tearing of the aluminum matrix with no loss of cohesion between the particles and matrix. The coefficient of thermal expansion decreased upon irradiation, with a maximum change of −6.3% for the annealed irradiated 36.5 vol% specimen.
Presentations:
"“Microstructure and mechanical properties of friction stir welded MA956" Ramprashad Prabhakaran, TMS 2009 Annual Meeting February 15-17, (2009)
"Friction stir welding of MA956 and MA754 ODS alloys" Ramprashad Prabhakaran, Materials science & technology (MS&T) 2010 October 17-21, (2010)
"Friction stir welding of oxide dispersion strengthened alloys" Ramprashad Prabhakaran, ANS 2010 annual meeting (NFSM) June 13-17, (2010)
"Irradiation studies on friction stir welded MA956 and MA754" Ramprashad Prabhakaran, TMS 2012 annual meeting March 11-15, (2012)
"Irradiation studies on friction stir welded ODS alloys" Ramprashad Prabhakaran, TMS 2013 Annual Meeting March 3-7, (2013)
"Microstructural and mechanical characteristics of friction stir welded ODS alloys" Ramprashad Prabhakaran, 2010 TMS Annual Meeting February 14-18, (2010)
"Microstructure and mechanical properties of friction stir welded MA956 and MA754" Ramprashad Prabhakaran, MS&T 2009 October 25-29, (2009)
"Microstructure and mechanical properties of irradiated friction stir welded ODS alloys" Ramprashad Prabhakaran, TMS 2011 annual meeting February 27-3, (2011)
"Small-scale specimen testing of irradiated MA 754 and MA 957 alloys" Ramprashad Prabhakaran, MS&T 2008 October 5-9, (2008)
"The effect of neutron irradiation on friction stir welded MA956 and MA754" Ramprashad Prabhakaran, Materials Science & Technology (MS&T) October 7-11, (2012)
NSUF Articles:
U.S. DOE Nuclear Science User Facilities Awards 30 Rapid Turnaround Experiment Research Proposals - Awards total nearly $1.2 million The U.S. Department of Energy (DOE) Nuclear Science User Facilities (NSUF) has selected 30 new Rapid Turnaround Experiment (RTE) projects, totaling up to approximately $1.2 million. These projects will continue to advance the understanding of irradiation effects in nuclear fuels and materials in support of the mission of the DOE Office of Nuclear Energy. Wednesday, April 26, 2017 - Calls and Awards
RTE 1st Call Awards Announced - Projects total approximately $1.4 million These projects will continue to advance the understanding of irradiation effects in nuclear fuels and materials in support of the mission of the DOE-NE. Friday, February 8, 2019 - Calls and Awards
DOE awards 39 RTE Projects - Projects total approximately $1.3 million Thursday, February 1, 2018 - Calls and Awards
DOE Awards 31 RTE Proposals, Opens FY-20 1st Call - Projects total $1.1 million; Next proposals due 10/31 Awards will go to 22 principal investigators from universities, six from national laboratories, and three from foreign universities. Tuesday, September 17, 2019 - Calls and Awards, Announcement
Users Organization Meeting Presentations Now Available - Wednesday, March 25, 2020 - Newsletter, Users Group
DOE Awards Eight CINR NSUF Projects - Projects include $3M in access grants and R&D funding Monday, July 6, 2020 - Calls and Awards
Department of Energy Nuclear Science User Facilities Awards 29 Rapid Turnaround Experiment Proposals - Awarded projects total nearly $1.14M in access awards Tuesday, June 8, 2021 - News Release, Calls and Awards
U.S. Department of Energy Announces FY21 CINR Awards - DOE has selected 4 NSUF projects U.S. Department of Energy (DOE) selected four projects that will take advantage of Nuclear Science User Facilities (NSUF) capabilities to investigate important nuclear fuel and material applications. Monday, June 28, 2021 - Calls and Awards
NSUF awards 28 Rapid Turnaround Experiment proposals - Approximately $1.74M has been awarded. The new call closes June 28. Thursday, June 1, 2023 - Calls and Awards
NSUF welcomes 2024 Users Organization Executive Committee - Tuesday, February 6, 2024 - Users Group
Additional Publications:
"Preliminary Characterization and Evaluation on ShAPE Manufactured 316H and ODS Steels" Mageshwari Komarasamy, Chinthaka Silva, Tanvi Anil Ajantiwalay, Quin Miller, Ramprashad Prabhakaran, Shalini Tripathi, Julian Escobar, Mayur Pole, David Garcia, Matthew Olszta, Tianhao Wang, Isabella van Rooyen, [2024] · DOI: 10.2172/2498398
"Irradiation-induced shift in the thermodynamic stability of phases and the self-healing effect in transformative high entropy alloys" Abhijeet Dhal, Zhihan Hu, Megha Dubey, Lin Shao, Ramprashad Prabhakaran, Rajiv S. Mishra, Priyanka Agrawal, [2024] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2024.155093
"Manufacturing Oxide Dispersion Strengthened (ODS) steel plate via cold spray and friction stir processing" Dalong Zhang, Jens T. Darsell, Kenneth A. Ross, Xiaolong Ma, Jia Liu, Tingkun Liu, Ramprashad Prabhakaran, Lan Li, Iver E. Anderson, Wahyu Setyawan, Xiang Wang, [2024] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2024.155076
"Ion irradiation and examination of Additive friction stir deposited 316 stainless steel" Ching-Heng Shiau, Aishani Sharma, Zhihan Hu, Megha Dubey, Yu Lu, Lin Shao, Ramprashad Prabhakaran, Yaqiao Wu, Rajiv S. Mishra, Priyanka Agrawal, [2024] Materials & Design · DOI: 10.1016/j.matdes.2024.112730
"Feasibility Evaluation of a Solid Phase Scalable HEA Cladding Manufacturing Route" , Subhashish Meher, Jorge Fernandez dos Santos, Mageshwari Komarasamy, Mohan Sai Kiran Kumar Yadav Nartu, Jonathan Wierschke, Ramprashad Prabhakaran, Nicole Overman, Irving Brown, Brian Milligan, Lei Li, Ayoub Soulami, David Garcia, Tianhao Wang, , Isabella Johanna van Rooyen, [2023] · DOI: 10.2172/2481594
"Influence of processing on secondary phase formation and microstructural evolution at U-10Mo alloy and Zr interlayer interfaces" Miao Song, Shawn Riechers, Adam Koziol, Samuel A. Briggs, Kayla Yano, Ramprashad Prabhakaran, Alan Schemer-Kohrn, Ayoub Soulami, Vineet V. Joshi, Arun Devaraj, Elizabeth J. Kautz, [2023] Journal of Alloys and Compounds · DOI: 10.1016/j.jallcom.2023.172074
"Thermomechanical Properties of Neutron Irradiated Al3Hf-Al Thermal Neutron Absorber Materials" Mychailo B. Toloczko, Ramprashad Prabhakaran, Yuanyuan Zhu, Yu Lu, Yaqiao Wu, Donna Post Guillen, [2023] Materials · DOI: 10.3390/ma16165518

A thermal neutron absorber material composed of Al3Hf particles in an aluminum matrix is under development for the Advanced Test Reactor. This metal matrix composite was fabricated via hot pressing of high-purity aluminum and micrometer-size Al3Hf powders at volume fractions of 20.0, 28.4, and 36.5%. Room temperature tensile and hardness testing of unirradiated specimens revealed a linear relationship between volume fraction and strength, while the tensile data showed a strong decrease in elongation between the 20 and 36.5% volume fraction materials. Tensile tests conducted at 200 °C on unirradiated material revealed similar trends. Evaluations were then conducted on specimens irradiated at 66 to 75 °C to four dose levels ranging from approximately 1 to 4 dpa. Tensile properties exhibited the typical increase in strength and decrease in ductility with dose that are common for metallic materials irradiated at ≤0.4Tm. Hardness also increased with neutron dose. The difference in strength between the three different volume fraction materials was roughly constant as the dose increased. Nanoindentation measurements of Al3Hf particles in the 28.4 vol% material showed the expected trend of increased hardness with irradiation dose. Transmission electron microscopy revealed oxygen at the interface between the Al3Hf particles and aluminum matrix in the irradiated material. Scanning electron microscopy of the exterior surface of tensile tested specimens revealed that deformation of the material occurs via plastic deformation of the Al matrix, cracking of the Al3Hf particles, and to a lesser extent, tearing of the matrix away from the particles. The fracture surface of an irradiated 28.4 vol% specimen showed failure by brittle fracture in the particles and ductile tearing of the aluminum matrix with no loss of cohesion between the particles and matrix. The coefficient of thermal expansion decreased upon irradiation, with a maximum change of −6.3% for the annealed irradiated 36.5 vol% specimen.

"Thermomechanical Properties of Neutron Irradiated Al3Hf-Al Thermal Neutron Absorber Materials" Mychailo B. Toloczko, Ramprashad Prabhakaran, Yuanyuan Zhu, Yu Lu, Yaqiao Wu, Donna Post Guillen, [2023] Materials · DOI: 10.3390/ma16165518

A thermal neutron absorber material composed of Al3Hf particles in an aluminum matrix is under development for the Advanced Test Reactor. This metal matrix composite was fabricated via hot pressing of high-purity aluminum and micrometer-size Al3Hf powders at volume fractions of 20.0, 28.4, and 36.5%. Room temperature tensile and hardness testing of unirradiated specimens revealed a linear relationship between volume fraction and strength, while the tensile data showed a strong decrease in elongation between the 20 and 36.5% volume fraction materials. Tensile tests conducted at 200 °C on unirradiated material revealed similar trends. Evaluations were then conducted on specimens irradiated at 66 to 75 °C to four dose levels ranging from approximately 1 to 4 dpa. Tensile properties exhibited the typical increase in strength and decrease in ductility with dose that are common for metallic materials irradiated at ≤0.4Tm. Hardness also increased with neutron dose. The difference in strength between the three different volume fraction materials was roughly constant as the dose increased. Nanoindentation measurements of Al3Hf particles in the 28.4 vol% material showed the expected trend of increased hardness with irradiation dose. Transmission electron microscopy revealed oxygen at the interface between the Al3Hf particles and aluminum matrix in the irradiated material. Scanning electron microscopy of the exterior surface of tensile tested specimens revealed that deformation of the material occurs via plastic deformation of the Al matrix, cracking of the Al3Hf particles, and to a lesser extent, tearing of the matrix away from the particles. The fracture surface of an irradiated 28.4 vol% specimen showed failure by brittle fracture in the particles and ductile tearing of the aluminum matrix with no loss of cohesion between the particles and matrix. The coefficient of thermal expansion decreased upon irradiation, with a maximum change of −6.3% for the annealed irradiated 36.5 vol% specimen.

"Irradiation response of innovatively engineered metastable TRIP high entropy alloy" Sanya Gupta, Abhijeet Dhal, Ramprashad Prabhakaran, Lin Shao, Rajiv S. Mishra, Priyanka Agrawal, [2023] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2022.154217
"Improved Understanding of Zircaloy Hydrogen Pickup Mechanisms in BWRs. NSUF Report (Final Report)" Gregory Coffey, Olga Marina, John Hardy, Danny Edwards, Andrew Casella, Ramprashad Prabhakaran, [2022] · DOI: 10.2172/1987523
"Characterization Report for the MP-1 Experiment Fabrication Campaign (Rev.1)" Fidelma Di Lemma, Tammy Trowbridge, Eric Tegtmeier, Rodney Mccabe, Ramprashad Prabhakaran, Nicole Overman, David Blanchard, Jason Schulthess, Chad Brizzee, Kevin Bohn, Jessica Lopez, Brieanna Alexander, Cody Miller, Nicholas Lombardo, Vineet Joshi, Rajib Kalsar, [2021] · DOI: 10.2172/2331300
"Characterization Report for the MP-1 Experiment Fabrication Campaign" Fidelma Di Lemma, Tammy Trowbridge, Eric Tegtmeier, Rodney McCabe, Ramprashad Prabhakaran, Nicole Overman, David Blanchard, Jason Schulthess, Chad Brizzee, Kevin Bohn, Jessica Lopez, Brieanna Alexander, Cody Miller, Nicholas Lombardo, Vineet Joshi, Rajib Kalsar, [2020] · DOI: 10.2172/1763443
"PNNL's Intermediate Characterization Summary for the MP-1 Experiment" Ramprashad Prabhakaran, Nicole Overman, David Blanchard, Vineet Joshi, Rajib Kalsar, [2019] · DOI: 10.2172/2346213
"Mechanical Characterization and Corrosion Testing Of X608 Al Alloy" Jung‐Pyung Choi, Elizabeth Stephens, David Catalini, Curt Lavender, Aashish Rohatgi, Ramprashad Prabhakaran, [2016] Light Metals 2016 · DOI: 10.1002/9781119274780.ch25 · EID: 2-s2.0-84982221003
"Mechanical characterization and corrosion testing of X608 A1 alloy" [2016] TMS Light Metals · EID: 2-s2.0-84974527553
"Foreword: TMS 2013: Materials and Fuels for the Current and Advanced Nuclear Reactors II" Ramprashad Prabhakaran, [2015] Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science · DOI: 10.1007/s11661-014-2626-1 · EID: 2-s2.0-84922005600
"An investigation of the mechanical properties of fresh and irradiated U-Mo fuels" [2010] Transactions of the American Nuclear Society · EID: 2-s2.0-79551661411
"Friction stir welding of oxide dispersion strengthened alloys" [2010] Transactions of the American Nuclear Society · EID: 2-s2.0-79551673099
"Properties of DU-10 wt% Mo alloys subjected to various post-rolling heat treatments" Ramprashad Prabhakaran, Thomas Hartmann, Jan-Fong Jue, Francine J. Rice, Douglas E. Burkes, [2010] Nuclear Engineering and Design · DOI: 10.1016/j.nucengdes.2010.02.008 · EID: 2-s2.0-77950949473
"Mechanical properties of DU-xMo alloys with x = 7 to 12 weight percent" Ramprashad Prabhakaran, Jan-Fong Jue, Francine J. Rice, Douglas E. Burkes, [2009] Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science · DOI: 10.1007/s11661-009-9805-5 · EID: 2-s2.0-64849105592
"Microstructural characteristics of DU-xMo alloys with x = 7-12 wt%" Thomas Hartmann, Ramprashad Prabhakaran, Jan-Fong Jue, Douglas E. Burkes, [2009] Journal of Alloys and Compounds · DOI: 10.1016/j.jallcom.2008.12.063 · EID: 2-s2.0-67349221484
"Small-scale specimen testing of monolithic fuels and structural materials" [2008] Transactions of the American Nuclear Society · EID: 2-s2.0-55249117240
"Degradations of Type 422 stainless steel in aqueous environments" Ajit K. Roy, Ramprashad Prabhakaran, [2006] Materials Science and Engineering A · DOI: 10.1016/j.msea.2006.01.094 · EID: 2-s2.0-33645985765
"Environment-assisted cracking of structural materials under different loading conditions" [2005] Corrosion · EID: 2-s2.0-18744380658
"Gas fast reactor fuel development" [2005] Transactions of the American Nuclear Society · EID: 2-s2.0-33244483636
"Stress corrosion cracking of nuclear transmutation structural materials" [2004] Materials Performance · EID: 2-s2.0-33845420629
"The effect of environmental and mechanical variables on stress corrosion cracking of a martensitic stainless steel for transmutation applications" [2004] Proceedings of the International Conference on Nuclear Engineering (ICONE12) · EID: 2-s2.0-10644221779
"Effect of environmental variables on cracking of martensitic stainless steels under different loading conditions" [2003] Global 2003: Atoms for Prosperity: Updating Eisenhowers Global Vision for Nuclear Energy · EID: 2-s2.0-2642560450
"Environment-induced degradation of spallation target materials" [2003] International Meeting on Nuclear Applications of Accelerator Technology: Accelerator Application in a Nuclear Renaissance · EID: 2-s2.0-2642532137
Source: ORCID/CrossRef using DOI
NSUF Research Collaborations

Advanced microstructure characterization of irradiation impact on corrosion performance of SiC-SiC composite materials - FY 2024 Super RTE Call, #24-5092

TEM characterization of neutron irradiated HT-9 as a function of irradiation temperature and dose - FY 2024 RTE 2nd Call, #24-4945

Elemental effects on radiation damage in tempered martensitic steels neutron irradiated to high doses at fast reactor relevant temperatures - FY 2024 CINR, #24-31447

Room Temperature Tensile Properties of ATR Neutron Irradiated T91 - FY 2023 RTE 2nd Call, #23-4705

Effect of ion irradiation and dose rates on 316LY oxide-dispersion-strengthened steel additively manufactured by laser-directed energy deposition - FY 2023 RTE 2nd Call, #23-4723

Ion Irradiation and Characterization of FeCrAl Oxide Dispersion Strengthend Alloy Manufactured via Laser Powder Bed Fusion - FY 2022 RTE 1st Call, #22-4400

Effect of neutron irradiation on the microstructure of NF616 (Grade 92) as a function of dose and temperature - FY 2022 RTE 1st Call, #22-4453

Ion Irradiation and Examination of Additive Friction Stir Manufactured 316 Stainless Steel Component - FY 2021 RTE 1st Call, #21-4307

Ion Irradiation and examination of 304 Stainless Steel and 304 ODS Steel Additively Manufactured via Selective Laser Melting - FY 2021 RTE 1st Call, #21-4352

Microstructural characterization of neutron irradiated HT-9 heats (ORNL, LANL and EBR II) at LWR and fast reactor relevant temperatures - FY 2020 RTE 2nd Call, #20-4201

Ion irradiation and examination of metastability engineered stainless high entropy alloy - FY 2020 RTE 2nd Call, #20-4112

Influence of Fast Neutron Irradiation on the Mechanical Properties and Microstructure of Nanostructured Metals/Alloys - FY 2008 Call for User Proposals, #08-96