Education

Research Description

Dr. Murty is interested in the deformation, creep, fatigue and fracture behaviors of nuclear core and pressure boundary materials, with particular emphasis on structure­property relationship and effects of radiation exposure.

Publications

A multi-deformation mechanisms assisted metastable beta-ZrTiAlV alloy exhibits high yield strength and high work hardening rate

Liao, Z., Luan, B., Zhang, X., Liu, R., Murty, K. L., & Liu, Q. (2020), JOURNAL OF ALLOYS AND COMPOUNDS, 816. https://doi.org/10.1016/j.jallcom.2019.152642

Accelerated crack growth experiments of SS304H for dry storage canister in substitute ocean water - Effect of temperature

Tjayadi, L., Kumar, N., & Murty, K. L. (2020), MATERIALS TODAY COMMUNICATIONS, 23. https://doi.org/10.1016/j.mtcomm.2020.100929

Characterization of stress-rupture behavior of nuclear-grade C26M2 FeCrAl alloy for accident-tolerant fuel cladding via burst testing

Joshi, P., Kombaiah, B., Cinbiz, M. N., & Murty, K. L. (2020), MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 791. https://doi.org/10.1016/j.msea.2020.139753

Correlation of microstructural, textural characteristics and hardness of Ti-6Al-4V sheet beta-cooled at different rates

Dai, J., Xia, J., Chai, L., Murty, K. L., Guo, N., & Daymond, M. R. (2020), JOURNAL OF MATERIALS SCIENCE. https://doi.org/10.1007/s10853-020-04603-9

Effect of hold time on high temperature creep-fatigue behavior of Fe-25Ni-20Cr (wt.%) austenitic stainless steel (Alloy 709)

Alsmadi, Z. Y., Alomari, A., Kumar, N., & Murty, K. L. (2020), MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 771. https://doi.org/10.1016/j.msea.2019.138591

Effect of varying a phase fraction on the mechanical properties and deformation mechanisms in a metastable beta-ZrTiAlV alloy

Liao, Z., Luan, B., Zhang, X., Liu, R., Murty, K. L., & Liu, Q. (2020), MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 772. https://doi.org/10.1016/j.msea.2019.138784

Microstructural characteristics and hardness of CoNiTi medium-entropy alloy coating on pure Ti substrate prepared by pulsed laser cladding

Xiang, K., Chai, L., Wang, Y., Wang, H., Guo, N., Ma, Y., & Murty, K. L. (2020), JOURNAL OF ALLOYS AND COMPOUNDS, 849. https://doi.org/10.1016/j.jallcom.2020.156704

Twinning behaviors and grain refinement mechanisms during friction stir processing of Zr alloy

Li, S., Luan, B., Chu, L., Zhang, X., Yuan, G., Liu, R., … Liu, Q. (2020), MATERIALS CHARACTERIZATION, 163. https://doi.org/10.1016/j.matchar.2020.110277

Biaxial Creep Behavior of Nb-Modified Zircaloys

Joshi, P., Tillman, M., Kumar, N., Murty, K., & Cinbiz, N. (2019), NUCLEAR TECHNOLOGY. https://doi.org/10.1080/00295450.2019.1674581

Creep Behavior and Microstructural Evolution of a Fe-20Cr-25Ni (Mass Percent) Austenitic Stainless Steel (Alloy 709) at Elevated Temperatures

Alomari, A. S., Kumar, N., & Murty, K. L. (2019), METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, 50A(2), 641–654. https://doi.org/10.1007/s11661-018-5044-y

View all publications via NC State Libraries

Grants

Development of an In-Situ Testing Laboratory for Research and Education of Very High Temperature Reactor Materials

US Dept. of Energy (DOE)(10/01/20 - 9/30/21)

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Development of an In-Situ Testing Laboratory for Research and Education of Very High Temperature Reactor Materials

Sponsor: US Dept. of Energy (DOE)

Start Date: 10/01/20

End Date: 9/30/21

Abstract

A novel thermo-mechanical fatigue (TMF) testing system, referred by miniature TMF (MTMF) system has been developed at NCSU for in-situ testing of miniature specimens within Scanning Electron Microscopes (SEM). The MTMF is capable of prescribing axial-torsional loading to solid specimen and axial-torsional-internal pressure loading to tubular specimen of 1 mm diameter at elevated temperatures (up to 1000oC) to investigate deformation of microstructure and failure mechanism in real time. Currently, in-situ SEM testing with the MTMF is performed at the Analytical Instrumentation Facility (AIF) at NCSU. This poses a serious restriction to investigate failure mechanisms of very high temperature reactor (VHTRs) materials primarily because with a user facility, such as AIF, we can only perform short-term tests that span over few days. However, fatigue, creep and creep-fatigue tests for VHTR materials may span from few days to several weeks. Hence, existing SEMs on campus are not available for long-term in-situ testing of VHTR materials. Currently, fatigue, creep and creep-fatigue failure mechanisms of new and existing alloys are mostly investigated through ex-situ testing or short duration in-situ uniaxial testing within SEM. Consequently, initiation and propagation of many failure mechanisms, especially interactions between creep and fatigue mechanisms in reducing high temperature component lives remain unknown. Hence, developing a shared in-situ testing laboratory (ISTL) is essential to allow NCSU researchers to perform novel research on nuclear materials addressing issues of fatigue, creep and creep-fatigue failure mechanisms. The proposed ISTL dedicated to performing long-term fatigue, creep and creep-fatigue tests is in critical need to develop design criteria of VHTR materials for ASME Code Sec III Div 5. However, existing facilities at NCSU or any other universities or national labs in the nation do not have a facility dedicated to perform long term tests representing realistic loading conditions of VHTR. Therefore, a suitable SEM compatible with the MTMF system at NCSU is proposed to be acquired to develop an ISTL to address high temperature nuclear materials and ASME Code issues. With the availability of such a ISTL, uniaxial and multiaxial cyclic experiments prescribing realistic thermo-mechanical fatigue (TMF), creep and creep-fatigue loading can be performed on specimens of VHTR materials, such as Alloy 617, 316H, 800H, Grade 91 steel, for addressing the high temperature component design and development issues. Finally, because of the size of commercially available TMF systems, these cannot be used for in-situ SEM testing, which is essential for investigating existing alloys and developing new alloy for VHTRs. Hence, acquisition of a SEM will give the NCSU research community unprecedented capability to perform fundamental research and educate next generation scientists in studying real-time long-term microstructure evolution of nuclear materials under uniaxial and multiaxial loading. In addition, the proposed equipment will allow training undergraduate and graduate students and postdocs in performing material characterization using advanced techniques and provide hands on experiences to students in various undergraduate and graduate courses.

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Novel Miniature Creep Tester for Virgin and Neutron Irradiated Clad Alloys with Benchmarked Multiscale Modeling and Simulations

US Dept. of Energy (DOE)(10/01/19 - 9/30/22)

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Novel Miniature Creep Tester for Virgin and Neutron Irradiated Clad Alloys with Benchmarked Multiscale Modeling and Simulations

Sponsor: US Dept. of Energy (DOE)

Start Date: 10/01/19

End Date: 9/30/22

Abstract

Fast and accurate measurements of creep are needed for qualifying new alloys for current and next generation reactors. For recently developed ferritic alloys such as FeCrAl, the lack of creep/fatigue data is more acute. To address this concern, this project will design and develop a novel miniature creep testing system for performing creep and load relaxation tests at multiple scales inside a scanning electron microscope (SEM). The primary objectives of the proposal are: (i) Collect rapid thermal creep and load relaxation data for two selected ferritic alloys: FeCrAl and oxide dispersed strengthened (ODS-14YWT) alloy at accelerated test conditions using solid, thin-walled and flat specimens under biaxial and uniaxial loading conditions across a temperature range of 500 ºC to 1000 ºC, (ii) Benchmark select data from miniature specimens against data from conventional creep tests with larger samples, (iii) Extract deformation mechanisms using in-situ SEM for virgin and neutron irradiated samples using the miniature tester, which otherwise is onerous with macroscopic creep equipment, and (iv) Perform mesoscale discrete dislocation dynamics (DD) simulations using information derived from SEM, and macroscopic constitutive modeling for predicting long-time behavior.

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North Carolina State University's Graduate Fellowship In Nuclear Engineering (NCSU-GFINE)– 2018

US Nuclear Regulatory Commission(8/30/19 - 8/29/23)

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North Carolina State University's Graduate Fellowship In Nuclear Engineering (NCSU-GFINE)– 2018

Sponsor: US Nuclear Regulatory Commission

Start Date: 8/30/19

End Date: 8/29/23

Abstract

This proposal is a request for financial support for two graduate students every year for four consecutive years in nuclear engineering through the North Carolina State University’s Graduate Fellowship in Nuclear Engineering (NCSU–GFINE) program that helps to develop a highly talented and competent workforce with post-baccalaureate education capable of leading the nation’s charge to reinvigorate its nuclear industry. Every attempt will be made during the recruitment and selection processes to ensure that the sponsored students reflect the diverse groups that make up our nation’s populace. Moreover, the high academic standards inherent to NC State’s Department of Nuclear Engineering and the proposed selection formula will ensure the highest caliber of the sponsored fellows. These individuals will shepherd the design, construction, operation, and regulation of new and innovative nuclear facilities, while maintaining the safety and security of processes for the handling of requisite nuclear materials in the coming decades, a period crucial for the revamping of an industry that has fallen to neglect. Upon graduation, the sponsored fellows will be contractually required to complete nuclear-related employment at the rate of six months per year of NCSU–GFINE sponsorship. The support of industry for the Department and its mission, and their interest in NCSU–GFINE is evidenced by hiring of our graduates.

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Mechanisms of Retention and Transport of Fission Products in Virgin and Irradiated Nuclear Graphite. Work Scope Identifier: RC-2.

US Dept. of Energy (DOE)(10/01/17 - 9/30/21)

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Mechanisms of Retention and Transport of Fission Products in Virgin and Irradiated Nuclear Graphite. Work Scope Identifier: RC-2.

Sponsor: US Dept. of Energy (DOE)

Start Date: 10/01/17

End Date: 9/30/21

Abstract

We propose a joint experimental-computational approach to measure the diffusivities of fission products – Iodine (I), Cesium (Cs), Krypton (Kr), Strontium (Sr), Ruthenium (Ru) and Silver (Ag), and Europium (Eu) in four graphite grades – HOPG, NBG-18, PCEA and IG-110, and uncover the mechanisms of transport using multiscale simulations involving electronic structure, atomistic, and phase field methods. By measuring the diffusivities in both virgin and neutron/ion irradiated samples (up to 25 dpa), we will probe the importance of radiation-induced defects and pores in fission product transport and retention. Non-radioactive species will be implanted into the graphite samples for simulating realistic fission product trajectories. We will leverage on our prior NEUP work on nuclear graphite, and will use ion and neutron irradiated samples from this project (NBG/HOPG/IG-110: ion irradiated, 1 and 25 dpa, PCEA: neutron irradiated, 6.61 and 10.16 dpa; in addition, the UoM will test samples from irradiated Gen I and Gen II nuclear graphite grades, some containing fission material.

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Effect of alloying and thermo-mechanical processing on biaxial creep of low c/a-ratio hexagonal closed packed metals (Zr-alloys)

National Science Foundation (NSF)(7/15/17 - 6/30/21)

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Effect of alloying and thermo-mechanical processing on biaxial creep of low c/a-ratio hexagonal closed packed metals (Zr-alloys)

Sponsor: National Science Foundation (NSF)

Start Date: 7/15/17

End Date: 6/30/21

Abstract

The proposal addresses the influence of thermo-mechanical-treatment (TMT) and alloying on creep anisotropy of Zircaloys that are commonly used in nuclear power reactors. The study involves characterization of anisotropic biaxial creep of Zircaloy-4 and HANA4 alloys with emphasis on the effects of recrystallization and Nb addition using closed-end internally pressurized thin-walled tubing superimposed with axial load. It is proposed here to investigate these behaviors following tube-reduction (Pilger milling), stress-relief anneal and complete recrystallization. Alloying addition of Nb has been shown to exhibit better characteristics particularly for extended use in the light water reactors with some modification of crystallographic texture and the operating slip systems and underlying creep mechanisms.

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Advanced Nuclear Materials Laboratory Enhancements for Corrosion and Stress Corrosion Testing

US Dept. of Energy (DOE)(10/01/17 - 9/30/19)

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Advanced Nuclear Materials Laboratory Enhancements for Corrosion and Stress Corrosion Testing

Sponsor: US Dept. of Energy (DOE)

Start Date: 10/01/17

End Date: 9/30/19

Abstract

Funding is requested, through the DOE NEUP Infrastructure program, to obtain the acquisition of autoclaves and equipment for Corrosion, Stress-assisted Corrosion, and Stress Corrosion Cracking testing of nuclear materials for structural and cladding applications in LWRs, and corrosion studies related to HLW storage packages. The proposed equipment and laboratory enhancements will be used in the performance of research related to existing DOE projects and proposed efforts in the areas of advanced nuclear fuels and materials. The equipment will also be used for the purpose of a laboratory class which is being developed by the PIs for inclusion in the curriculum. The 1 credit Lab is in complement to the 3 credit Nuclear Materials Science class. It will also be of relevance for a class on Corrosion of Nuclear Materials developed by two of the co-PIs at the graduate level which will cover issues related to corrosion and stress corrosion of materials used in nuclear reactors. Henceforward, the requested infrastructure will also enable/enhance the Teaching/Learning Mission of the NE department at NCSU.

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Tribological Damage Mechanisms from Experiments and Validated Simulations of Alloy 800H and Inconel 617 in a Simulated HTGR/VHTR Helium Environment

US Dept. of Energy (DOE)(10/01/16 - 9/30/20)

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Tribological Damage Mechanisms from Experiments and Validated Simulations of Alloy 800H and Inconel 617 in a Simulated HTGR/VHTR Helium Environment

Sponsor: US Dept. of Energy (DOE)

Start Date: 10/01/16

End Date: 9/30/20

Abstract

The purpose of this proposal to develop a mechanistic understanding of accelerated fretting and wear, and bonding between Alloy 800H and Inconel 617 surfaces, we propose a series of tribological experiments in a simulated helium environment with controlled concentrations of gaseous specious, attendant microstructure characterization using electron microscopy, spectroscopy and atom-probe tomography, validated continuum models, and constitutive equations at the macroscale informed by mechanisms at the atomistic level. Our experimental data and insights derived from modeling and simulations will support ASME qualification of Alloy 800H and Inconel 617 in the new ASME Division-5 that provides construction rules for high temperature reactors and liquid metal reactors.

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North Carolina State University’s Graduate Fellowship in Nuclear Engineering (NCSU–GFINE) - 2016

US Nuclear Regulatory Commission(7/01/16 - 6/30/20)

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North Carolina State University’s Graduate Fellowship in Nuclear Engineering (NCSU–GFINE) - 2016

Sponsor: US Nuclear Regulatory Commission

Start Date: 7/01/16

End Date: 6/30/20

Abstract

This proposal is a request for financial support for 2 graduate students in nuclear engineering through the North Carolina State University’s Graduate Fellowship in Nuclear Engineering (NCSU–GFINE) program that helps to develop a highly talented and competent workforce with post-baccalaureate education capable of leading the nation’s charge to reinvigorate its nuclear industry. Every attempt will be made during the recruitment and selection processes to ensure that the sponsored students reflect the diverse groups that make up our nation’s populace. Moreover, the high academic standards inherent to NC State’s Department of Nuclear Engineering and the proposed selection formula will ensure the highest caliber of the sponsored fellows. These individuals will shepherd the design, construction, operation, and regulation of new and innovative nuclear facilities, while maintaining the safety and security of processes for the handling of requisite nuclear materials in the coming decades, a period crucial for the revamping of an industry that has fallen to neglect. Upon graduation the sponsored fellows will be contractually required to complete nuclear-related employment at the rate of six months per year of NCSU–GFINE sponsorship. The commitment by NCSU’s Department of Nuclear Engineering and College of Engineering to the success of NCSU–GFINE is evidenced by a cost-sharing contribution.

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National Academy for Nuclear Training Fellowship Program 2015-2016

Institute of Nuclear Power Operations (INPO)(1/01/16 - 12/31/16)

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National Academy for Nuclear Training Fellowship Program 2015-2016

Sponsor: Institute of Nuclear Power Operations (INPO)

Start Date: 1/01/16

End Date: 12/31/16

Abstract

This proposal is to request the continued participation of NCSU Nuclear Engineering in the National Academy for Nuclear Training Fellowship Program. The support level of one student per year at $25,000 is requested.

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Innovative Approach to SCC Inspection and Evaluation of Canister in Dry Storage

US Dept. of Energy (DOE)(10/01/15 - 9/30/19)

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Innovative Approach to SCC Inspection and Evaluation of Canister in Dry Storage

Sponsor: US Dept. of Energy (DOE)

Start Date: 10/01/15

End Date: 9/30/19

Abstract

Major effort will be on SCC fracture characterization of SSs along with evaluation of KISCC and crack-growth rates in 304 and 304L stainless steel welds in marine environments. The appropriate materials with welds/HAZs will be provided by CSM and subsize WOL specimens will be fabricated from these steel samples. This is the subsize modified Manjoine fracture test specimen with 20% side-groove for straight growth of the crack as per ASTM standards. Main reason for selecting WOL type specimens is that a value of KISCC can be determined from a single specimen at the arrest condition thereby avoiding dependence on the initial loading level. The WOL specimens will be fatigue precracked at different loads to different precrack lengths. Sufficiently large load will be applied so that K value larger than KISCC is applied using a bolt under constant load-line displacement. The crack is allowed to grow until arrest which takes place since K decreases with increasing crack length. Crack lengths will be monitored by DC potential drop method that allows continuous monitoring of the crack growth. An online data acquisition system will be used along with specially developed software for continuous recording of data including time variations of load (using internally strain-gauged bolts), DC drop and crack-length as well as K.

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