Lin Shao

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Professor Lin Shao
Texas A&M University
Texas A&M University
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Lin Shao (Texas A&M University) is Robert Cochran University Professor of Nuclear Engineering at Texas A&M University. He received a BS degree from Peking University and Ph.D. from Univ. of Houston, both in Physics. Prior to joining TAMU, he was Director Funded Postdoctoral Fellow at Los Alamos National Laboratory. Dr. Shao’s primary research interests are ion-solid interaction and the development of damage-resistant materials. He has published four book chapters, over 260 journal papers and frequently served as Chair for International Conferences (IBMM 2018, REM 10, and AccApp'21). Currently, he is Director of the Accelerator Laboratory at Texas A&M University. Dr. Shao received a Postdoctoral Distinguished Performance Award from Los Alamos National Laboratory in 2006 and the inaugural IBMM Prize in 2008 for his past contributions in the ion beam field. He also received the 2009 NSF career award and numerous teaching and research awards at TAMU. He is an ANS fellow. 

Ab intio calculations, cracking, ion beam analysis, Ion irradiaiton, Molecular dynamcis simulations, Neutron Irradiation, Nuclear materials, Radiation induced hardening, Rate theory simulations, Sensors, Steels, Void Swelling
"A Preliminary Investigation of High Dose Ion Irradiation Response of a Lanthana-Bearing Nanostructured Ferritic Steel Processed via Spark Plasma Sintering" Somayeh Pasebani, Indrajit Charit, Ankan Guria, Yaqiao Wu, Jatuporn Burns, Darryl Butt, James Cole, Lin Shao, Journal of Nuclear Materials Vol. 495 2017 78-84 Link
A lanthana-containing nanostructured ferritic steel (NFS) was processed via mechanical alloying (MA) of Fe-14Cr-1Ti-0.3Mo-0.5La2O3 (wt.%) and consolidated via spark plasma sintering (SPS). In order to study the consolidation behavior via SPS, sintering temperature and dwell time were correlated with microstructure, density, microhardness and shear yield strength of the sintered specimens. A bimodal grain size distribution including both micron-sized and nano-sized grains was observed in the microstructure of specimens sintered at 850, 950 and 1050 oC for 45 min. Significant densification occurred at temperatures greater than 950 oC with a relative density higher than 98%. A variety of nanoparticles, some enriched in Fe and Cr oxides and copious nanoparticles smaller than 10 nm with faceted morphology and enriched in La and Ti oxides were observed. After SPS at 950 oC, the number density of Cr-Ti-La-O enriched nanoclusters with an average radius of 1.5 nm was estimated to be 1.2 ×10^24 m^-3 . The La + Ti : O ratio was close to 1 after SPS at 950 and 1050 C; however, the number density of nanoclusters decreased at 1050 C. With SPS above 950 C, the density improved but the microhardness and shear yield strength decreased due to partial coarsening of the grains and nanoparticles.
"Damage tolerant nanotwinned metals with nanovoids under radiation environments" Youxing Chen, Kaiyuan Yu, Lin Shao, Haiyan Wang, Mark KirK, Jian Wang, Xinghang Zhang, Nature Communications Vol. 6 2015 Link
"Effect of dpa rate on the temperature regime of void swelling in ion-irradiated pure chromium" Adam Gabriel, Laura Hawkins, Aaron French, Yongchang Li, Zhihan Hu, Lingfeng He, Pengyuan Xiu, Michael Nastasi, Frank Garner, Lin Shao, JNM Vol. 561 2022 Link
"Effect of laser welding on deformation mechanisms in irradiated austenitic stainless steel" Janelle Wharry, Keyou Mao, Cheng Sun, Xiang Liu, Haozheng Qu, Aaron French, Paula Freyer, Frank Garner, Lin Shao, Journal of Nuclear Materials Vol. 528 2020 151878 Link
Deformation mechanism of a laser weld on neutron irradiated AISI 304L stainless steel was studied by in-situ microcompression test at room temperature. The deformation-induced austenite-to-martensite phase transformation occurs in {101}-oriented grains in the irradiated base metal, while deformation twinning prevails in {101}-oriented grains in the weld heat affected zone (HAZ). A high number density of irradiation-induced voids in the base metal provides sufficient nucleation sites for the austenite-to-martensite phase transformation under compression at room temperature. A deformation map is established to predict critical twinning stress for face-centered-cubic (fcc) metals and alloys. Our results show that irradiation-induced voids can tailor the deformation mechanisms of austenitic stainless steel.
"Enhanced radiation tolerance of ultrafine grained Fe–Cr–Ni alloy" Yingtao Liu, Lin Shao, Cheng Sun, Journal of Nuclear Materials Vol. 420 2012 235 Link
The evolutions of microstructure and mechanical properties of Fe–14Cr–16Ni (wt.%) alloy subjected to Helium ion irradiations were investigated. Equal channel angular pressing (ECAP) process was used to significantly reduce the average grain size from 700 lm to 400 nm. At a peak fluence level of 5.5 displacement per atom (dpa), helium bubbles, 0.5–2 nm in diameter, were observed in both coarse-grained (CG) and ultrafine grained (UFG) alloy. The density of He bubbles, dislocation loops, as well as radiation hardening were reduced in the UFG Fe–Cr–Ni alloy comparing to those in its CG counterpart. The results imply that radiation tolerance in bulk metals can be effectively enhanced by refinement of microstructures.
"Influence of injected interstitials on the void swelling in two structural variants of 304L stainless steel induced by self-ion irradiation at 500 °C" Cheng Sun, Frank Garner, Lin Shao, Xinghang Zhang, Stuart Maloy, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms Vol. 409 2017 323-327 Link
"Intermetallic formation and interdiffusion in diffusion couples made of uranium and single crystal ion" Tianyi Chen, Bulent Sencer, Lin Shao, Travis Smith, Jonathan Gigax, Di Chen, Robert Balerio, Bulent Sencer, Rory Kennedy, Journal of Nuclear Materials Vol. 467 2015 82-88 Link
We studied the interfacial phase formation and diffusion kinetics in uranium–iron diffusion couples. A comparison was made between polycrystalline uranium (U) bonded with polycrystalline iron (FeP) and polycrystalline uranium bonded with single crystalline Fe (FeSC). After thermal annealing at 575 °C, 600 °C, 625 °C and 650 °C, respectively, diffusion and microstructures at the interface were characterized by scanning electron microscopy and transmission electron miscopy. The presence of grain boundaries in iron has a significant influence on interface reactions. In comparison with U–FeP system, interdiffusion coefficients of the U–FeSC system are significantly lower and were governed by much higher activation energies. Integrated interdiffusion coefficients and intrinsic diffusion coefficients were obtained. The intrinsic diffusion coefficients show faster diffusion of iron atoms in both U6Fe and UFe2 intermetallic phases than uranium.
"Irradiation Damage Behavior in Novel High-Entropy Carbide Ceramics" Bai Cui, Fei Wang, Xueliang Yan, Lin Shao, Michael Nastasi, Transactions of the American Nuclear Society Vol. 120 2019 327
"Irradiation damage in (Zr0.25Ta0.25Nb0.25Ti0.25)C high-entropy carbide ceramics" Bai Cui, Fei Wang, Xueliang Yan, Lin Shao, Tianyao Wang, Yaqiao Wu, Michael Nastasi, Yongfeng Lu, Acta Materialia Vol. 2020
"Irradiation-induced swelling of pure chromium with 5 MeV Fe ions in the temperature range 450–650 °C" Lin Shao, Journal of Nuclear Materials Vol. 543 2021 152585 Link
A surface coating using pure chromium has been proposed to increase the accident tolerance of Zircaloy cladding in pressurized water reactors. However, there is not much irradiation experience with Cr alloys and especially pure Cr. In the present study, pure chromium was irradiated with 5 MeV Fe ions to 50 peak dpa (displacements per atom) at temperatures of 450, 500, 550, 600 and 650 °C. Then irradiation at the peak swelling temperature of 550 °C was conducted to 50, 100, 150 peak dpa. Swelling at 50 dpa was observed over the entire temperature range studied, 450–650 °C, but appeared to be decreasing strongly at the temperature boundaries of the experiment. After an initial transient of rapid swelling, chromium was observed to swell at a rate of ~0.03–0.04%/dpa (up to 120 local dpa), which is much lower than pure Fe at 0.2%/dpa. This low swelling rate was found to be relatively insensitive to dpa rate, which varied by a factor of ~2 over the depth of data collection. Swelling was observed to begin quickly with an incubation period less than 10 dpa. Self-organization in the form of void ordering was observed to be developing at 50 dpa, becoming better defined with increasing dose. The void alignment direction is determined to be the 〈111〉 axial direction.
"Microstructural changes of proton irradiated Hastelloy-N and in situ micropillar compression testing of one single grain at different local damage levels" Miguel Pena, Andres Morell-Pacheco, Ching-Heng Shiau, Boopathy Kombaiah, Lingfeng He, Laura Hawkins, Adam Gabriel, Frank Garner, Lin Shao, JNM Vol. 2022 Link
"Microstructural stability of a self-ion irradiated lanthana-bearing nanostructured ferritic steel" SULTAN ALSAGABI, Darryl Butt, Indrajit Charit, James Cole, Somayeh Pasebani, Lin Shao, Jatuporn Burns, Lloyd Price, Journal of Nuclear Materials Vol. 462 2015 191-204 Link
Thermally stable nanofeatures with high number density are expected to impart excellent high temperature strength and irradiation stability in nanostructured ferritic steels (NFSs) which have potential applications in advanced nuclear reactors. A lanthana-bearing NFS (14LMT) developed via mechanical alloying and spark plasma sintering was used in this study. The sintered samples were irradiated by Fe2+ ions to 10, 50 and 100 dpa at 30 °C and 500 °C. Microstructural and mechanical characteristics of the irradiated samples were studied using different microscopy techniques and nanoindentation, respectively. Overall morphology and number density of the nanofeatures remained unchanged after irradiation. Average radius of nanofeatures in the irradiated sample (100 dpa at 500 °C) was slightly reduced. A notable level of irradiation hardening and enhanced dislocation activity occurred after ion irradiation except at 30 °C and ⩾50 dpa. Other microstructural features like grain boundaries and high density of dislocations also provided defect sinks to assist in defect removal.
"Microstructure and microchemistry of laser welds of irradiated austenitic steels" Keyou Mao, Aaron French, Xiang Liu, Lucille Giannuzzi, Cheng Sun, Megha Dubey, Paula Freyer, Jonathan Tatman, Frank Garner, Lin Shao, Janelle Wharry, Materials and Design Vol. 206 2021 Link
"Orientation-selected micro-pillar compression of additively manufactured 316L stainless steels: Comparison of as-manufactured, annealed, and proton-irradiated variants" Ching-Heng Shiau, Cheng Sun, Michael McMurtrey, Frank Garner, Lin Shao, JNM Vol. 566 2022 Link
"Radiation damage in nanostructured materials" Xinghang Zhang, Khalid Hattar, Youxing Chen, Lin Shao, Jin Li, Cheng Sun, Kaiyuan Yu, Nan Li, Mitra Taheri, Haiyan Wang, Progress in Materials Science Vol. 96 2018 217-321 Link
"Radiation effects on interface reactions of U/Fe, U/(Fe + Cr), and U/(Fe + Cr + Ni)" Bulent Sencer, Lin Shao, Yongho Sohn, Di Chen, Chaochen Wei, Michael Martin, Xuemei Wang, Young Joo Park, Ed Dein, Kevin Coffey, Rory Kennedy, Journal of Nuclear Materials Vol. 456 2015 302-310 Link
We study the effects of radiation damage on interdiffusion and intermetallic phase formation at the interfaces of U/Fe, U/(Fe + Cr), and U/(Fe + Cr + Ni) diffusion couples. Magnetron sputtering is used to deposit thin films of Fe, Fe + Cr, or Fe + Cr + Ni on U substrates to form the diffusion couples. One set of samples are thermally annealed under high vacuum at 450 °C or 550 °C for one hour. A second set of samples are annealed identically but with concurrent 3.5 MeV Fe++ ion irradiation. The Fe++ ion penetration depth is sufficient to reach the original interfaces. Rutherford backscattering spectrometry analysis with high fidelity spectral simulations is used to obtain interdiffusion profiles, which are used to examine differences in U diffusion and intermetallic phase formation at the buried interfaces. For all three diffusion systems, Fe++ ion irradiations enhance U diffusion. Furthermore, the irradiations accelerate the formation of intermetallic phases. In U/Fe couples, for example, the unirradiated samples show typical interdiffusion governed by Fick’s laws, while the irradiated ones show step-like profiles influenced by Gibbs phase rules.
"Role of cavities on deformation-induced martensitic transformation pathways in a laser-welded, neutron irradiated austenitic stainless steel" Janelle Wharry, Keyou Mao, Cheng Sun, Ching-Heng Shiau, Kayla Yano, Paula Freyer, Anter EL-AZAB, Frank Garner, Aaron French, Lin Shao, Scripta Materialia Vol. 178 2020 1-6 Link
The role of cavities on deformation-induced martensitic phase transformations is studied in a laser-welded and neutron irradiated austenitic stainless steel. Orientation dependent nanoindentation experiments are performed in the base metal and the weld heat affected zone (HAZ) at room temperature. Transmission electron microscopy study of deformed microstructures indicates indentation-induced α’-martensite forms in the base metal, whereas α’- and ε-martensite arise in the HAZ. The different pathway of martensite phase transformation is attributed to the laser weld-induced annealing of cavities. Our results suggest that deformation-induced martensitic phase transformation of austenitic stainless steel is correlated to neutron irradiated cavity structures.
"Superior radiation-resistant nanoengineered austenitic 304L stainless steel for applications in extreme radiation environments" Cheng Sun, Lin Shao, Steven Zinkle, Todd Allen, Haiyan Wang, Xinghang Zhang, Scientific Reports Vol. 5 2015 Link
"Understanding the Phase Equilibrium and Irradiation Effects in Fe-Zr Diffusion Couples" Assel Aitkaliyeva, Bulent Sencer, Lin Shao, Yongho Sohn, Chao-Chen Wei, Zhiping Luo, Ashley Ewh, Rory Kennedy, Michael Myers, Joseph Wallace, M. J. General, Michael Martin, Journal of Nuclear Materials Vol. 432 2013 205-211 Link
We have studied the radiation effects in Fe–Zr diffusion couples, formed by thermal annealing of a mechanically bonded binary system at 850 °C for 15 days. After irradiation with 3.5 MeV Fe ions at 600 °C, a cross sectional specimen was prepared by using a focused-ion-beam-based lift out technique and was characterized using scanning/transmission electron microscopy, selected-area diffraction and X-ray energy dispersive spectroscopy analyses. Comparison studies were performed in localized regions within and beyond the ion projected range and the following observations were obtained: (1) the interaction layer consists of FeZr3, FeZr2, Fe2Zr, and Fe23Zr6; (2) large Fe23Zr6 particles with smaller core particles of Zr-rich Fe2Zr are found within the a-Fe matrix; (3) Zr diffusion is significantly enhanced in the ion bombarded region, leading to the formation of an Fe–Zr compound; (4) grains located within the interaction layer are much smaller in the ion bombarded region and are associated with new crystal growth and nanocrystal formation; and (5) large a-Fe particles form on the surface of the Fe side, but the particles are limited to the region close to the interaction layer. These studies reveal the complexity of the interaction phase formation in an Fe–Zr binary system and the accelerated microstructural changes under irradiation.
NSUF Articles:
U.S. DOE Nuclear Science User Facilities Awards 35 Rapid Turnaround Experiment Research Proposals - Awards total approximately $1.3 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, September 20, 2017 - Calls and Awards
RTE 2nd Call Awards Announced - Projects total approximately $1.6 million These project awards went to principal investigators from 26 U.S. universities, eight national laboratories, two British universities, and one Canadian laboratory. Tuesday, May 14, 2019 - Calls and Awards
NSUF Research Collaborations

Alleviating irradiation-induced precipitation in a Fe-21Cr-5Al alloy via nanostructuring. - FY 2019 RTE 2nd Call, #1761

Atom Probe Tomography Study of Elemental Segregation and Precipitation in Ion-Irradiated Advanced Austenitic Alloy A709 - FY 2020 RTE 1st Call, #2963

Atom Probe Tomography Study of Helium precipitates in amorphous/crystalline SiOC/Fe nanocomposites - FY 2018 RTE 2nd Call, #1385

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

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

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

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

Ion-Irradiation and Microstructural Change Studies of Glassy Carbon - FY 2019 RTE 3rd Call, #2878

Irradiation Damage in (Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)C High-Entropy Ceramics - FY 2018 RTE 3rd Call, #1589

Microstructural and nanomechanical characterization of a lanthana-bearing nanostructured ferritic steel irradiated with high dose iron irons - FY 2015 RTE 1st Call, #543

The influence of proton irradiation damage on the corrosion of Hastelloy N exposed to FliNaK molten salt - FY 2019 RTE 3rd Call, #2833

Unraveling the Mystery of Irradiation-Induced Void Closure - FY 2020 RTE 1st Call, #2946