Amey Khanolkar

Profile Information
Name
Dr. Amey Khanolkar
Institution
Idaho National Laboratory
Position
Applied Physicist
h-Index
ORCID
0000-0003-0816-5507
Biography

Amey is an Applied Physicist in the Materials Science and Manufacturing Department at INL. He received his BS and MS degrees in mechanical engineering from Drexel University in Philadelphia, PA in 2013, and a PhD in mechanical engineering from the University of Washington in Seattle, WA in 2018. Amey joined the INL as a Russell L. Heath Distinguished Postdoctoral Fellow in 2019. Prior to joining INL, Amey was a postdoctoral researcher within the Mechanical and Aerospace Engineering Department at the University of California San Diego. As an undergraduate student, Amey was a research intern at the Federal Aviation Administration’s Technical Center in Atlantic City, NJ. His research interests broadly include developing laser ultrasonic techniques to assess defects in material microstructure, and tailoring stress waves with novel phononic structures and metamaterials. His doctoral thesis investigated ultrasonic wave tailoring phenomena in micro-scale granular materials using a variety of laser ultrasonic techniques. At INL, Amey is currently studying thermal transport and elastic wave propagation in ion-irradiated oxide and metallic materials under the Center for Thermal Energy Transport under Irradiation.

Expertise
Elastic Properties, In-pile Sensors, Ion-Irradiation, Microstructure, Nuclear Materials, Oxide Fuels, Thermal Conductivity
Publications:
"An integrated experimental and computational investigation of defect and microstructural effects on thermal transport in thorium dioxide" Marat Khafizov, Lingfeng He, Cody Dennett, David Hurley, Zilong Hua, Amey Khanolkar, Anter EL-AZAB, Kaustubh Bawane, Acta Materialia Vol. 213 2021 Link
"Inferring Relative Dose-dependent Color Center Populations in Proton Irradiated Thoria Single Crystals using Optical Spectroscopy" Marat Khafizov, Amey Khanolkar, David Hurley, Cody Dennett, Zilong Hua, James Mann, Physical Chemistry Chemical Physics Vol. 24 2022 Link
Presentations:
"Influence of Irradiation-induced Microstructural Defects on the Thermal Conductivity of Single Crystal Thorium Dioxide" Marat Khafizov, Amey Khanolkar, Zilong Hua, Cody Dennett, wangthink Wang, Tiankai Yao, Lingfeng He, Jian Gan, David Hurley, TMS 2020 February 23-27, (2020)
Additional Publications:
"Experimental confirmation of first-principles thermal conductivity in Zirconium-doped ThO2" Zilong Hua, Amey Khanolkar, J. Matthew Mann, David B. Turner, Karl Rickert, Timothy A. Prusnick, Marat Khafizov, David H. Hurley, Linu Malakkal, Ella Kartika Pek, [2025] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2025.155756
"Adhesion Testing of Direct-Write Printed Ink on Metallic Structural Components" Amey R. Khanolkar, James A. Smith, Bradley C. Benefiel, Shaun P. Evans, Michael D. McMurtrey, David Estrada, Brian J. Jaques, Timothy L. Phero, [2025] IEEE Open Journal of Instrumentation and Measurement · DOI: 10.1109/ojim.2024.3517622
"Molecular beam epitaxy of superconducting zirconium nitride on GaN substrates" Sabin Regmi, Amey R. Khanolkar, Volodymyr Buturlim, Zachery E. Cresswell, Kevin D. Vallejo, Krzysztof Gofryk, David H. Hurley, Brelon J. May, [2024] AIP Advances · DOI: 10.1063/5.0242982

Epitaxial integration of metals and semiconductors can enable enhanced performance and novel functionality. Achieving such pristine interfaces with superconducting materials is of increasing interest for quantum devices and detectors, but the experimental demonstration remains challenging, given the very limited studies on single crystalline systems. To expand the potential materials for these systems, this work explores the deposition of zirconium nitride superconducting thin films on GaN substrates at various temperatures using molecular beam epitaxy. A general trend of decreasing superconducting critical temperature is observed as the deposition temperature is reduced. The optical properties reveal a transition from metallic to dielectric behavior with colder deposition. The plasma frequency of the metallic films is also observed to be a function of growth temperature. These results pave the way for the integration of a highly tunable metal nitride with a well-established semiconductor system.

"Effects of irradiation damage on the hardness and elastic properties of quaternary and high entropy transition metal diborides" Amit Datye, Yan Zhang, Cody A. Dennett, Weiming Guo, Yang Liu, William J. Weber, Hua-Tay Lin, Yanwen Zhang, Amey Khanolkar, [2024] Journal of Applied Physics · DOI: 10.1063/5.0206224

Multi-principal component transition metal (TM) diborides represent a class of high-entropy ceramics (HECs) that have received considerable interest in recent years owing to their promising properties for extreme environment applications that include thermal/ environmental barriers, hypersonic vehicles, turbine engines, and next-generation nuclear reactors. While the addition of chemical disorder through the random distribution of TM elements on the cation sublattice has offered opportunities to tailor elastic stiffness and hardness, the effects of irradiation-induced structural damage on the physical properties of these complex materials have remained largely unexplored. To this end, changes in the hardness and elastic moduli of a high-entropy TM diboride (Hf0.2Nb0.2Ta0.2Ti0.2Zr0.2)B2 and three of its quaternary subsets following irradiation with 10 MeV gold (Au) ions to fluences of up to 6 × 1015 Au cm−2 are investigated at the micrometer and sub-micrometer length-scales via the dispersion of laser-generated surface acoustic waves (SAW) and nanoindentation, respectively. The nanoindentation measurements show that the TM diborides exhibit an initial increase in hardness following irradiation with energetic Au ions, with a subsequent decrease in hardness following further irradiation. One quaternary composition, (Hf1/3Ta1/3Ti1/3)B2, exhibits a notable exception to the trend and continues to exhibit an increase in hardness with ion irradiation fluence. Although differences in the absolute values of the effective elastic moduli obtained from the measured SAW dispersion and nanoindentation are observed (and attributed to microstructural variations at the measurement length-scale), both techniques yield similar trends in the form of an initial reduction and subsequent saturation in the elastic modulus with increasing ion irradiation fluence. The quaternary TM diboride (Hf1/3Ta1/3Ti1/3)B2 again exhibits a departure from this trend. The high-entropy TM diboride (Hf0.2Nb0.2Ta0.2Ti0.2Zr0.2)B2 exhibits the greatest recovery in hardness and modulus when irradiated to high ion fluences following initial changes at low fluence, indicating superior resistance to radiation-induced damage over its quaternary counterparts. Opportunities for designing HECs with superior hardness and modulus for enhanced radiation resistance (compared to their single constituent counterparts) by tailoring chemical disorder and bond character in the lattice are discussed.

"Optical pulse-induced ultrafast antiferrodistortive transition in SrTiO3" Amey Khanolkar, Shuxiang Zhou, David H. Hurley, Marat Khafizov, Saqeeb Adnan, [2024] Applied Physics Reviews · DOI: 10.1063/5.0194334

The ultrafast dynamics of the antiferrodistortive phase transition in perovskite SrTiO3 is monitored via time-domain Brillouin scattering. Using femtosecond optical pulses, we initiate a thermally driven tetragonal-to-cubic structural transformation and detect the crystal phase through changes in the frequency of Brillouin oscillations (BO) induced by propagating acoustic phonons. Coupling the measured BO frequency with a spatiotemporal heat diffusion model, we demonstrate that, for a sample kept in the tetragonal phase, deposition of sufficient thermal energy induces a rapid transformation of the heat-affected region to the cubic phase. The initial phase change is followed by a slower reverse cubic-to-tetragonal phase transformation occurring on a timescale of hundreds of picoseconds. We attribute this ultrafast phase transformation in the perovskite to a structural resemblance between atomic displacements of the R-point soft optic mode of the cubic phase and the tetragonal phase, both characterized by anti-phase rotation of oxygen octahedra. The structural relaxation time exhibits a strong temperature dependence consistent with the prediction of the equation of motion describing collective oxygen octahedra rotation based on the energy landscape of the phenomenological Landau theory of phase transitions. Evidence of such a fast structural transition in perovskites can open up new avenues in information processing and energy storage sectors.

"Physical Properties and Their Influence on Irradiation Damage in Metal Diborides and in High-Entropy Materials" Amey R. Khanolkar, Kaustubh K. Bawane, Cody A. Dennett, Zilong Hua, Krzysztof Gofryk, Boopathy Kombaiah, Weiming Guo, Yang Liu, William J. Weber, Yanwen Zhang, Hua-Tay Lin, Yan Zhang, [2024] JOM · DOI: 10.1007/s11837-024-06486-6
"Thermal conductivity suppression in uranium-doped thorium dioxide due to phonon-spin interactions" Saqeeb Adnan, Amey R. Khanolkar, Karl Rickert, David B. Turner, Timothy A. Prusnick, J. Matthew Mann, David H. Hurley, Marat Khafizov, Cody A. Dennett, Zilong Hua, [2024] Journal of Materiomics · DOI: 10.1016/j.jmat.2023.11.007
"Printed Strain Gauges for High Temperature Applications (>300°C)" Amey Khanolkar, Michael McMurtrey, Timothy Phero, [2023] · DOI: 10.2172/2339691
"High temperature elastic properties of sub-stoichiometric yttrium dihydrides" Mahmut N. Cinbiz, Jianguo Yu, Xunxiang Hu, Amey Khanolkar, [2023] Materials Today Communications · DOI: 10.1016/j.mtcomm.2023.105879
"Temperature-dependent elastic constants of thorium dioxide probed using time-domain Brillouin scattering" Yuzhou Wang, Cody A. Dennett, Zilong Hua, J. Matthew Mann, Marat Khafizov, David H. Hurley, Amey Khanolkar, [2023] Journal of Applied Physics · DOI: 10.1063/5.0148866

We report the adiabatic elastic constants of single-crystal thorium dioxide over a temperature range of 77–350 K. Time-domain Brillouin scattering, an all-optical, non-contact picosecond ultrasonic technique, is used to generate and detect coherent acoustic phonons that propagate in the bulk perpendicular to the surface of the crystal. These coherent acoustic lattice vibrations have been monitored in two hydrothermally grown single-crystal thorium dioxide samples along the (100) and (311) crystallographic directions. The three independent elastic constants of the cubic crystal (C11, C12, and C44) are determined from the measured bulk acoustic velocities. The longitudinal wave along the (100) orientation provided a direct measurement of C11. Measurement of C44 and C12 was achieved by enhancing the intensity of quasi-shear mode in a (311) oriented crystal by adjusting the polarization angle relative to the crystal axes. We find the magnitude of softening of the three elastic constants to be ∼2.5% over the measured temperature range. Good agreement is found between the measured elastic constants with previously reported values at room temperature, and between the measured temperature-dependent bulk modulus with calculated values. We find that semi-empirical models capturing lattice anharmonicity adequately reproduce the observed trend. We also determine the acoustic Grüneisen anharmonicity parameter from the experimentally derived temperature-dependent bulk modulus and previously reported temperature-dependent values of volumetric thermal expansion coefficient and heat capacity. This work presents measurements of the temperature-dependent elasticity in single-crystal thorium dioxide at cryogenic temperature and provides a basis for testing ab initio theoretical models and evaluating the impact of anharmonicity on thermophysical properties.

"A combined theoretical-experimental investigation of thermal transport in low-dose irradiated thorium dioxide" Amey Khanolkar, Sanjoy Mazumder, Cody A. Dennett, Kaustubh Bawane, Zilong Hua, Joshua Ferrigno, Lingfeng He, J. Matthew Mann, Marat Khafizov, David H. Hurley, Anter El-Azab, W. Ryan Deskins, [2022] Acta Materialia · DOI: 10.1016/j.actamat.2022.118379
"Radiolytic Gas Production from Aluminum Coupons (Alloy 1100 and 6061) in Helium Environments—Assessing the Extended Storage of Aluminum Clad Spent Nuclear Fuel" Xiaofei Pu, Amey Khanolkar, Trishelle M. Copeland-Johnson, Corey D. Pilgrim, Joseph R. Wilbanks, Elizabeth H. Parker-Quaife, Gregory P. Horne, Jacy K. Conrad, [2022] Materials · DOI: 10.3390/ma15207317

Corrosion of aluminium alloy clad nuclear fuel, during reactor operation and under subsequent wet storage conditions, promotes the formation of aluminium hydroxide and oxyhydroxide layers. These hydrated mineral phases and the chemisorbed and physisorbed waters on their surfaces are susceptible to radiation-induced processes that yield molecular hydrogen gas (H2), which has the potential to complicate the long-term storage and disposal of aluminium clad nuclear fuel through flammable and explosive gas mixture formation, alloy embrittlement, and pressurization. Here, we present a systematic study of the radiolytic formation of H2 from aluminium alloy 1100 (AA1100) and 6061 (AA6061) coupons in “dry” (~0% relative humidity) and “wet” (50% relative humidity) helium environments. Cobalt-60 gamma irradiation of both aluminium alloy types promoted the formation of H2, which increased linearly up to ~2 MGy, and afforded G-values of 1.1 ± 0.1 and 2.9 ± 0.1 for “dry” and “wet” AA1100, and 2.7 ± 0.1 and 1.7 ± 0.1 for “dry” and “wet” AA6061. The negative correlation of H2 production with relative humidity for AA6061 is in stark contrast to AA1100 and is attributed to differences in the extent of corrosion and varying amounts of adsorbed water in the two alloys, as characterized using optical profilometry, scanning electron microscopy, Raman spectroscopy, and X-ray diffraction techniques.

"Development of Quality Control Methods for Robust and Reliable Sensor Design" Amey Khanolkar, Kiyo Fujimoto, James Smith, Michael McMurtrey, Timothy Phero, [2022] · DOI: 10.2172/1901810
"Milestone 1.2.10: Steady-state H2 “roll over” point data for aluminum alloys 1100 and 6061" Jacy Conrad, Trishelle Copeland-Johnson, Xiaofei Pu, Amey Khanolkar, Joseph Wilbanks, Corey Pilgrim, Gregory Horne, [2022] · DOI: 10.2172/1968315
"Inferring relative dose-dependent color center populations in proton irradiated thoria single crystals using optical spectroscopy" Cody A. Dennett, Zilong Hua, J. Matthew Mann, David H. Hurley, Marat Khafizov, Amey Khanolkar, [2022] Physical Chemistry Chemical Physics · DOI: 10.1039/d1cp05191a

Transparent thoria crystals developed a deep blue color when exposed to energetic protons due to electrons trapped at oxygen vacancy sites. Optical spectroscopy offers a promising pathway to characterize the population of such atomic-level defects that cannot be imaged using electron microscopy.

"Origin of photoelastic phenomena in Ge-Se network glasses" Amey R. Khanolkar, Julien Ari, Pierre Deymier, Pierre Lucas, Lizhu Li, [2021] Physical Review B · DOI: 10.1103/physrevb.104.214209
"Laser-based Adhesion Strength Measurements for Advanced Manufactured Sensor Adhesion Characterization" Kiyo Fujimoto, Michael McMurtrey, Amey Khanolkar, [2021] · DOI: 10.2172/1813576
"An integrated experimental and computational investigation of defect and microstructural effects on thermal transport in thorium dioxide" W. Ryan Deskins, Marat Khafizov, Zilong Hua, Amey Khanolkar, Kaustubh Bawane, Lyuwen Fu, J. Matthew Mann, Chris A. Marianetti, Lingfeng He, David H. Hurley, Anter El-Azab, Cody A. Dennett, [2021] Acta Materialia · DOI: 10.1016/j.actamat.2021.116934
"The influence of lattice defects, recombination, and clustering on thermal transport in single crystal thorium dioxide" Zilong Hua, Amey Khanolkar, Tiankai Yao, Phyllis K. Morgan, Timothy A. Prusnick, Narayan Poudel, Aaron French, Krzysztof Gofryk, Lingfeng He, Lin Shao, Marat Khafizov, David B. Turner, J. Matthew Mann, David H. Hurley, Cody A. Dennett, [2020] APL Materials · DOI: 10.1063/5.0025384

Thermal transport is a key performance metric for thorium dioxide in many applications where defect-generating radiation fields are present. An understanding of the effect of nanoscale lattice defects on thermal transport in this material is currently unavailable due to the lack of a single crystal material from which unit processes may be investigated. In this work, a series of high-quality thorium dioxide single crystals are exposed to 2 MeV proton irradiation at room temperature and 600 °C to create microscale regions with varying densities and types of point and extended defects. Defected regions are investigated using spatial domain thermoreflectance to quantify the change in thermal conductivity as a function of ion fluence as well as transmission electron microscopy and Raman spectroscopy to interrogate the structure of the generated defects. Together, this combination of methods provides important initial insight into defect formation, recombination, and clustering in thorium dioxide and the effect of those defects on thermal transport. These methods also provide a promising pathway for the quantification of the smallest-scale defects that cannot be captured using traditional microscopy techniques and play an outsized role in degrading thermal performance.

"Nanocontact Tailoring via Microlensing Enables Giant Postfabrication Mesoscopic Tuning in a Self‐Assembled Ultrasonic Metamaterial" Amey Khanolkar, Han Zhao, Nicholas Boechler, Maroun Abi Ghanem, [2020] Advanced Functional Materials · DOI: 10.1002/adfm.201909217
Abstract

The ability to tune the resonant frequency of a self‐assembled ultrasonic metamaterial with mesoscale spatial resolution, after fabrication, by up to 250% is demonstrated. This tunability is achieved by the microlensing‐enabled modification of nanocontact features, wherein the metamaterial resonant elements “dig in” to the substrate. In addition to tunability exceeding prior MHz–GHz frequency ultrasonic metamaterial examples, the system presented herein can be tuned after assembly at a spatial resolution commensurate with the laser spot's diameter. It is posited that these aforementioned advantages will enable a new class of ultrasonic gradient index devices, such as ultrasonic elastic wave cloaks, that can be manufactured in a scalable manner and then rapidly tuned. Finally, it is expected that this large tunability at ultrasonic frequencies will have broader application to areas including optomechanics, acoustoplasmonics, quantum‐mechanical oscillators, and adhesion control.

"Erratum: “A self-assembled metamaterial for Lamb waves” [Appl. Phys. Lett. 107, 071903 (2015)]" S. Wallen, M. Abi Ghanem, J. Jenks, N. Vogel, N. Boechler, A. Khanolkar, [2019] Applied Physics Letters · DOI: 10.1063/1.5095407
"Longitudinal eigenvibration of multilayer colloidal crystals and the effect of nanoscale contact bridges" Amey Khanolkar, Samuel P. Wallen, Mary Helwig, Morgan Hiraiwa, Alexei A. Maznev, Nicolas Vogel, Nicholas Boechler, Maroun Abi Ghanem, [2019] Nanoscale · DOI: 10.1039/c8nr08453j

Longitudinal contact-based vibrations of colloidal crystals with a controlled layer thickness are studied.

"Spatial Laplace transform for complex wavenumber recovery and its application to the analysis of attenuation in acoustic systems" S. Raetz, M. Hiraiwa, M. Abi Ghanem, S. P. Wallen, A. Khanolkar, N. Boechler, J. Laurent, C. Prada, A. Duclos, P. Leclaire, J.-P. Groby, A. Geslain, [2016] Journal of Applied Physics · DOI: 10.1063/1.4963827

We present a method for the recovery of complex wavenumber information via spatial Laplace transforms of spatiotemporal wave propagation measurements. The method aids in the analysis of acoustic attenuation phenomena and is applied in three different scenarios: (i) Lamb-like modes in air-saturated porous materials in the low kHz regime, where the method enables the recovery of viscoelastic parameters; (ii) Lamb modes in a Duralumin plate in the MHz regime, where the method demonstrates the effect of leakage on the splitting of the forward S1 and backward S2 modes around the Zero-Group Velocity point; and (iii) surface acoustic waves in a two-dimensional microscale granular crystal adhered to a substrate near 100 MHz, where the method reveals the complex wavenumbers for an out-of-plane translational and two in-plane translational-rotational resonances. This method provides physical insight into each system and serves as a unique tool for analyzing spatiotemporal measurements of propagating waves.

"Resonant attenuation of surface acoustic waves by a disordered monolayer of microspheres" A. Vega-Flick, M. Hiraiwa, A. Khanolkar, T. Gan, N. Boechler, N. Fang, K. A. Nelson, A. A. Maznev, J. K. Eliason, [2016] Applied Physics Letters · DOI: 10.1063/1.4941808

Attenuation of surface acoustic waves (SAWs) by a disordered monolayer of polystyrene microspheres is investigated. Surface acoustic wave packets are generated by a pair of crossed laser pulses in a glass substrate coated with a thin aluminum film and detected via the diffraction of a probe laser beam. When a 170 μm-wide strip of micron-sized spheres is placed on the substrate between the excitation and detection spots, strong resonant attenuation of SAWs near 240 MHz is observed. The attenuation is caused by the interaction of SAWs with a contact resonance of the microspheres, as confirmed by acoustic dispersion measurements on the microsphere-coated area. Frequency-selective attenuation of SAWs by such a locally resonant metamaterial may lead to reconfigurable SAW devices and sensors, which can be easily manufactured via self-assembly techniques.

"Laser-induced transient grating setup with continuously tunable period" J. K. Eliason, A. A. Maznev, A. Khanolkar, M. Abi Ghanem, N. Boechler, J. J. Alvarado-Gil, K. A. Nelson, A. Vega-Flick, [2015] Review of Scientific Instruments · DOI: 10.1063/1.4936767

We present a modification of the laser-induced transient grating setup enabling continuous tuning of the transient grating period. The fine control of the period is accomplished by varying the angle of the diffraction grating used to split excitation and probe beams. The setup has been tested by measuring dispersion of bulk and surface acoustic waves in both transmission and reflection geometries. The presented modification is fully compatible with optical heterodyne detection and can be easily implemented in any transient grating setup.

"A self-assembled metamaterial for Lamb waves" S. Wallen, M. Abi Ghanem, J. Jenks, N. Vogel, N. Boechler, A. Khanolkar, [2015] Applied Physics Letters · DOI: 10.1063/1.4928564

We report the design and characterization of a self-assembled, locally resonant acoustic metamaterial for Lamb waves, composed of a monolayer of 1.02 μm polystyrene microspheres adhered to a 1.27 μm thick free-standing silicon membrane. A laser-induced transient grating technique is used to generate Lamb waves in the metamaterial and to measure its acoustic response. The measurements reveal a microsphere contact resonance and the lowest frequency spheroidal microsphere resonance. The measured dispersion curves show hybridization of flexural Lamb waves with the microsphere contact resonance. We compare the measured dispersion with an analytical model using the contact resonance frequency as a single fitting parameter, and find that it well describes the observed hybridization. This study may lead to an improved understanding of microscale contact mechanics and to the design of new types of acoustic metamaterials.

Source: ORCID/CrossRef using DOI