Materials Science, Metals and Alloys, Materials Chemistry, Surfaces, Coatings and Films
24
Scopus Publications
1101
Scholar Citations
15
Scholar h-index
18
Scholar i10-index
Scopus Publications
Retarded relaxation of grain boundaries’ non-equilibrium state in medium-entropy CoFeNi alloy probed by radiotracer diffusion Bhawna Yadav, Aditya Burla, G. Mohan Muralikrishna, N. Chandrasekaran, K.G. Pradeep, Mayur Vaidya, Gerhard Wilde, Sergiy V. Divinski Scripta Materialia, 2026 Grain boundary diffusion of Co in a high-pressure torsion-processed equiatomic CoFeNi medium-entropy alloy was investigated using radiotracer technique. The results revealed a retarded relaxation of deformation-induced, non-equilibrium state of grain boundaries. With increasing temperature, the formation and subsequent dissolution of the BCC phase at grain boundaries were observed, while atom probe tomography revealed nanoscale phase separation into Ni-rich FCC and FeCo-rich BCC regions. The combined effects of segregation and chemical complexity are proposed to stabilize the deformation-induced non-equilibrium grain boundary state. High-energy/high-diffusivity grain boundaries are found to survive even after high-temperature annealing treatments due to the chemical complexity of the medium-entropy alloy.
Grain boundary diffusion and segregation of Cr in Ni Σ11(1̄13)[110] bicrystals: Decoding the role of grain boundary defects Shraddha V. Sevlikar, G. Mohan Muralikrishna, Daniel Gaertner, Sergei Starikov, Tobias Brink, Daniel Scheiber, Daria Smirnova, Daniel Irmer, Bengü Tas, Vladimir A. Esin, Vsevolod I. Razumovskiy, Christian H. Liebscher, Gerhard Wilde, Sergiy V. Divinski Acta Materialia, 2024 Grain boundary diffusion of Cr in a near Σ11(1̄13)[110] Ni bicrystal is measured over a temperature interval between 503 K and 1203 K using the radiotracer technique. The grain boundary diffusion coefficients, Dgb, and the triple products, P=s⋅δ⋅Dgb, are determined in the C- and B-type kinetics regimes, respectively, with s being the segregation factor and δ the grain boundary width. Opposite to expectations, two distinct contributions to short-circuit diffusion along the nominally single interface are distinguished and related to the existence of two macroscopic facets with distinct grain boundary inclinations and, as a result, distinct structures. The experimental results indicate that the segregation factor of Cr in Ni is about unity, which is fully supported by ab initio calculations. Using classical atomistic simulations, Ni grain boundary self-diffusion coefficients are calculated for the symmetric and asymmetric facets. The computational simulations reveal accelerated self-diffusion kinetics along the asymmetric facet, attributing this phenomenon to the presence of disconnection-like defects. This elucidates the experimentally observed diffusion dynamics of chromium atoms, thereby corroborating the heterogeneous mechanisms governing atomic migration across distinct facets.
Demystifying the Semiconductor-to-Metal Transition in Amorphous Vanadium Pentoxide: The Role of Substrate/Thin Film Interfaces A. Carmel Mary Esther, G. Mohan Muralikrishna, Manohar Chirumamilla, Manoel da Silva Pinto, Stefan Ostendorp, Martin Peterlechner, Alexander Yu Petrov, Manfred Eich, Sergiy V. Divinski, Horst Hahn, Gerhard Wilde Advanced Functional Materials, 2024 The precise mechanism governing the reversible semiconductor‐to‐metal transition (SMT) in V2O5 remains elusive, yet its investigation is of paramount importance due to the remarkable potential of V2O5 as a versatile “smart” material in advancing optoelectronics, plasmonics, and photonics. In this study, distinctive experimental insights into the SMT occurring in amorphous V2O5 through the application of highly sensitive, temperature‐dependent, in situ analyses on a V2O5 thin film deposited on soda‐lime glass are presented. The ellipsometry measurements reveal that the complete SMT occurs at ≈340 °C. Remarkably, the refractive index and extinction coefficients exhibit reversible characteristics across visible and near‐infrared wavelengths, underscoring the switch‐like behavior inherent to V2O5. The findings obtained from ellipsometry are substantiated by calorimetry and in situ secondary ion mass spectrometry analyses. In situ electron microscopy observations unveil a separation of oxidation states within V2O5 at 320 °C, despite the thin film retaining its amorphous state. The comprehensive experimental investigations effectively demonstrate that alterations in electronic state can trigger the SMT in amorphous V2O5. It is revealed for the first time that the SMT in V2O5 is solely contingent upon electronic state changes, independent of structural transitions, and importantly, it is a reversible transformation within the amorphous state itself.
Grain boundary diffusion in a compositionally complex alloy: Interplay of segregation, precipitation and interface structures in a Ni–Cr–Mo alloy Baixue Bian, Lana Söltzer, G. Mohan Muralikrishna, Shabnam Taheriniya, Sandipan Sen, K.C. Hari Kumar, Sankaran S., Gerhard Wilde, Sergiy V. Divinski Acta Materialia, 2024 Grain boundary complexions in the Hastelloy C-22 are modified to unravel the structure–property interplay of grain boundary precipitation (carbides), segregation, and grain boundary diffusion rates. Annealing treatments are used to create distinct grain boundary complexions with specific segregation-precipitation-structure states. Two grain boundary states were compared: those induced by low- (at 873 K, mainly for segregation) and by high-temperature (at 1123 K, for carbide precipitation) annealing treatments. A correlative analytical microscopy–tracer diffusion analysis approach is followed to elucidate the influence of the carbide formation, element segregation, and structure evolution on grain boundary diffusion. The tracer measurements with the 51Cr and 63Ni radioisotopes reveal a strongly non-linear dependence of the grain boundary diffusion rates on the pre-annealing time. Via in-depth characterization of the grain boundary microstructure, the evolution of Mo segregation and of incoherent metallic carbides at the interfaces is quantitatively related to the captured monotonic grain boundary diffusion behavior in Ni–Cr–Mo system.
Microstructure stability and self-diffusion in the equiatomic HfScTiZr HCP multi-principal element alloy G. Mohan Muralikrishna, Sandipan Sen, Sai Kumaran Ayyappan, S. Sankaran, K. Guruvidyathri, Juliana Schell, Lukasz Rogal, Xi Zhang, Joachim Mayer, Blazej Grabowski, Gerhard Wilde, Sergiy V. Divinski Journal of Alloys and Compounds, 2024 Tracer diffusion of 44Ti, 46Sc and 89Zr in the hexagonal close-packed (HCP) HfScTiZr multicomponent alloy is investigated using the radiotracer technique. The microstructure stability is thoroughly examined by conducting prolonged heat treatments between 873 K and 1373 K to mimic the diffusion conditions. Electron microscopy analysis reveals that the alloy contains a mixture of two HCP phases with similar lattice constants, among which the major phase is enriched in Sc, whereas the minor phase is strongly enriched in Ti. The thermal stability is assessed by ab initio-informed calculations which support the existence of the two HCP phases. The Sc diffusion coefficients differ markedly between the HCP phases, while only marginal influence is found for the diffusion of Zr and Ti. The Arrhenius parameters are determined, i.e., the activation energy and the pre-factor. The diffusion properties are analyzed in correlation with the microstructure stability and the ab initio-informed thermodynamic results. The DFT-calculated mean squared atomic displacements, which represent the lattice distortions, are found to provide an appropriate parameter for predicting the diffusion trends of the individual elements. The phase analysis is further compared with existing CALPHAD-type predictions, and the discrepancies between the theoretical assessments and experimental observations are examined and discussed.
Coupling of alloy chemistry, diffusion and structure by grain boundary engineering in Ni–Cr–Fe Baixue Bian, Shabnam Taheriniya, G. Mohan Muralikrishna, Sandipan Sen, Christoph Gammer, Ingo Steinbach, Sergiy V. Divinski, Gerhard Wilde Acta Materialia, 2024 The diffusion–microstructure correlations for grain boundaries (GBs) in the technologically-relevant Ni-based 602CA alloy are investigated. Prolonged annealing treatments up to 744 h create distinct GB complexions with specific segregation–precipitation–structure states. Globular M23C6-type carbides at straight GBs and plate-like carbides together with NiAl-enriched (γ′-type) particles at hackly GBs are found to co-exist. Moreover, an atomic-scale GB spinodal-like decomposition, especially at straight GBs, is observed. The co-existence of the two distinct states of general high-angle GBs, indicated by tracer diffusion experiments and verified by a detailed structure examination, is explained via state-of-the-art measurements of local elastic strains. In a course of annealing at 873 K, the relatively “fast” diffusivities are found to increase by a factor of 10 or more as a result of a coupled evolution of the GB plate-like precipitates and the irregular GB structures, whereas the relatively ”slow” diffusivites remained practically unchanged representing the contributions of straight interfaces with spherical precipitates. Thus, the diffusion properties of high-angle GBs evolve together with characteristic changes of GB complexions distinguished by a growth of carbide- and γ′-type precipitates and a concomitant generation of GB dislocation networks. The obtained results provide novel insights into grain boundary tailoring by utilizing structure – kinetics correlations involving segregation, precipitation and the evolution of interface defects.
Evolution of phase constitution with mechanical alloying and spark plasma sintering of nanocrystalline Al xCoCrFeNi (x = 0, 0.3, 0.6, 1 mol) high-entropy alloys Rahul Bhattacharya, Murugesan Annasamy, Pavel Cizek, M. Kamaraj, G. Mohan Muralikrishna, Peter Hodgson, Daniel Fabijanic, B. S. Murty Journal of Materials Research, 2022 Nanocrystalline Al_ x CoCrFeNi ( x = 0, 0.3, 0.6, 1 mol) high-entropy alloys were synthesized by mechanical alloying (MA) and consolidated by spark plasma sintering (SPS). Single-phase face-centered cubic (FCC) structure was achieved with x = 0 and 0.3. Dual-phase body-centered cubic (BCC)/B2 + FCC structure was obtained in x = 0.6 and 1. Complete solid solution was achieved with a significantly reduced duration of MA (10 h) followed by a brief SPS leading to crystallite size of < 10 nm for MA powders and < 60 nm post-SPS. Incremental changes in Al content translate into increase of BCC + B2 phase fraction and alter the co-existing FCC phase composition consequently. Ni dominates FCC phase of CoCrFeNi and Al_0.3CoCrFeNi, whereas Fe dominates FCC phase of Al_0.6CoCrFeNi and AlCoCrFeNi. Carbon and Oxygen addition during milling process resulted in nanoscale dispersion of Cr_7C_3 carbide and Cr_2O_3 /Al_2O_3 post-SPS. The hardness of AlCoCrFeNi (730HV_0.3) was the highest among all MA-SPS alloys. Graphical abstract
Tracer diffusion in the σ phase of the CoCrFeMnNi system Jingfeng Zhang, G. Mohan Muralikrishna, Alex Asabre, Yordan Kalchev, Julian Müller, Benjamin Butz, Sven Hilke, Harald Rösner, Guillaume Laplanche, Sergiy V. Divinski, Gerhard Wilde Acta Materialia, 2021
Retarded relaxation of grain boundaries’ non-equilibrium state in medium-entropy CoFeNi alloy probed by radiotracer diffusion B Yadav, A Burla, GM Muralikrishna, N Chandrasekaran, KG Pradeep, ... Scripta Materialia 275, 117162 , 2026 2026
Grain boundary diffusion in compositionally complex alloys: A comprehensive review B Yadav, G Mohan Muralikrishna, M Vaidya, G Wilde, SV Divinski International Materials Reviews , 2025 2025 Citations: 5
Grain-and interphase boundary diffusion in eutectic AlCoCrFeNi2. 1 compositionally complex alloy H Zhang, GM Muralikrishna, A Akbari, H Rösner, BJ Tyler, SV Divinski, ... Acta Materialia 294, 121082 , 2025 2025 Citations: 15
The impact of non-equilibrium vacancies on mobilities and Kirkendall porosity formation in diffusion couples: Experiments and theory for the Cu–Fe–Ni system as a case study GM Muralikrishna, N Esakkiraja, J Kundin, F Hisker, J Berndt, S Klemme, ... Acta Materialia 292, 121035 , 2025 2025 Citations: 4
Grain boundary diffusion and segregation of Cr in Ni Σ11 (1̄13)[110] bicrystals: Decoding the role of grain boundary defects SV Sevlikar, GM Muralikrishna, D Gaertner, S Starikov, T Brink, ... Acta Materialia 278, 120229 , 2024 2024 Citations: 16
Demystifying the semiconductor‐to‐metal transition in amorphous vanadium pentoxide: the role of substrate/thin film interfaces ACM Esther, GM Muralikrishna, M Chirumamilla, MS Pinto, S Ostendorp, ... Advanced functional materials 34 (30), 2309544 , 2024 2024 Citations: 9
Grain boundary diffusion in a compositionally complex alloy: Interplay of segregation, precipitation and interface structures in a Ni–Cr–Mo alloy B Bian, L Söltzer, GM Muralikrishna, S Taheriniya, S Sen, KCH Kumar, ... Acta Materialia 269, 119803 , 2024 2024 Citations: 33
Microstructure stability and self-diffusion in the equiatomic HfScTiZr HCP multi-principal element alloy GM Muralikrishna, S Sen, SK Ayyappan, S Sankaran, K Guruvidyathri, ... Journal of Alloys and Compounds 976, 173196 , 2024 2024 Citations: 8
Coupling of alloy chemistry, diffusion and structure by grain boundary engineering in Ni–Cr–Fe B Bian, S Taheriniya, GM Muralikrishna, S Sen, C Gammer, I Steinbach, ... Acta Materialia 264, 119602 , 2024 2024 Citations: 17
Aluminium Matrix Composites: B2 Aluminide Strengthening D Srinu, Y Palguna, GM Muralikrishna, R Korala, K Srinivasarao, ... Transactions of Indian Institute of Metals , 2023 2023 Citations: 2
Kinetic and structural insights into the grain boundary phase transitions in Ni-Bi alloys B Bian, S Taheriniya, GM Muralikrishna, A Godha, SK Makineni, ... Acta Materialia 245, 118632 , 2023 2023 Citations: 14
Evolution of phase constitution with mechanical alloying and spark plasma sintering of nanocrystalline Al x CoCrFeNi ( x = 0, 0.3, 0.6, 1 mol) high-entropy alloys R Bhattacharya, M Annasamy, P Cizek, M Kamaraj, GM Muralikrishna, ... Journal of Materials Research 37 (4), 959-975 , 2022 2022 Citations: 28
Interface‐Driven Thermoelectric Switching Performance of VO + ‐Diffused Soda‐Lime Glass CME Alphonse, MM Garlapati, BJ Tyler, HF Arlinghaus, SV Divinski, ... physica status solidi (RRL)–Rapid Research Letters 15 (7), 2100077 , 2021 2021 Citations: 2
Tracer diffusion in the σ phase of the CoCrFeMnNi system J Zhang, GM Muralikrishna, A Asabre, Y Kalchev, J Mueller, B Butz, ... Acta Materialia 203, 116498 , 2021 2021 Citations: 49
Composition dependence of tracer diffusion coefficients in Fe–Ga alloys: A case study by a tracer-diffusion couple method GM Muralikrishna, B Tas, N Esakkiraja, VA Esin, KCH Kumar, IS Golovin, ... Acta Materialia 203, 116446 , 2021 2021 Citations: 31
Atomic transport in B2-ordered Al (Fe, Ni) alloys: Tracer-interdiffusion couple approach GM Muralikrishna, VA Esin, KN Kulkarni, BS Murty, G Wilde, SV Divinski Intermetallics 126, 106920 , 2020 2020 Citations: 16
Visualisation of stabilising particles at the gas-solid interface of metal foams V Pamidi, GM Muralikrishna, S Bhogi, K Georgy, B Muduli, ... Materials Letters 278, 128371 , 2020 2020 Citations: 4
Novel multicomponent B2-ordered aluminides: compositional design, synthesis, characterization, and thermal stability GM Muralikrishna, ACM Esther, K Guruvidyathri, P Watermeyer, ... Metals 10 (11), 1411 , 2020 2020 Citations: 24
Composition dependence of tracer diffusion coefficients in Fe-Ga alloys: a case study by a tracer-interdiffusion couple method GM Muralikrishna, B Tas, N Esakkiraja, V Esin, KC Kumar, IS Golovin, ... arXiv preprint arXiv:2008.12533 , 2020 2020
MOST CITED SCHOLAR PUBLICATIONS
High-entropy alloys by mechanical alloying: A review M Vaidya, GM Muralikrishna, BS Murty Journal of Materials Research 34 (5), 664-686 , 2019 2019 Citations: 563
Influence of Al content on thermal stability of nanocrystalline AlxCoCrFeNi high entropy alloys at low and intermediate temperatures MM Garlapati, M Vaidya, A Karati, S Mishra, R Bhattacharya, BS Murty Advanced Powder Technology 31 (5), 1985-1993 , 2020 2020 Citations: 71
Experimental assessment of the thermodynamic factor for diffusion in CoCrFeNi and CoCrFeMnNi high entropy alloys M Vaidya, GM Muralikrishna, SV Divinski, BS Murty Scripta Materialia 157, 81-85 , 2018 2018 Citations: 52
Microstructure and doping effect on the enhancement of the thermoelectric properties of Ni doped Dy filled CoSb 3 skutterudites V Trivedi, M Battabyal, P Balasubramanian, GM Muralikrishna, PK Jain, ... Sustainable Energy & Fuels 2 (12), 2687-2697 , 2018 2018 Citations: 50
Tracer diffusion in the σ phase of the CoCrFeMnNi system J Zhang, GM Muralikrishna, A Asabre, Y Kalchev, J Mueller, B Butz, ... Acta Materialia 203, 116498 , 2021 2021 Citations: 49
Influence of mechanically activated annealing on phase evolution in Al 0.3 CoCrFeNi high-entropy alloy R John, A Karati, MM Garlapati, M Vaidya, R Bhattacharya, D Fabijanic, ... Journal of Materials Science 54 (23), 14588-14598 , 2019 2019 Citations: 35
Grain boundary diffusion in a compositionally complex alloy: Interplay of segregation, precipitation and interface structures in a Ni–Cr–Mo alloy B Bian, L Söltzer, GM Muralikrishna, S Taheriniya, S Sen, KCH Kumar, ... Acta Materialia 269, 119803 , 2024 2024 Citations: 33
Composition dependence of tracer diffusion coefficients in Fe–Ga alloys: A case study by a tracer-diffusion couple method GM Muralikrishna, B Tas, N Esakkiraja, VA Esin, KCH Kumar, IS Golovin, ... Acta Materialia 203, 116446 , 2021 2021 Citations: 31
Evolution of phase constitution with mechanical alloying and spark plasma sintering of nanocrystalline Al x CoCrFeNi ( x = 0, 0.3, 0.6, 1 mol) high-entropy alloys R Bhattacharya, M Annasamy, P Cizek, M Kamaraj, GM Muralikrishna, ... Journal of Materials Research 37 (4), 959-975 , 2022 2022 Citations: 28
Novel multicomponent B2-ordered aluminides: compositional design, synthesis, characterization, and thermal stability GM Muralikrishna, ACM Esther, K Guruvidyathri, P Watermeyer, ... Metals 10 (11), 1411 , 2020 2020 Citations: 24
Tracer diffusion in ordered pseudo-binary multicomponent aluminides GM Muralikrishna, M Vaidya, BS Murty, SV Divinski, G Wilde Scripta Materialia 178, 227-231 , 2020 2020 Citations: 19
Coupling of alloy chemistry, diffusion and structure by grain boundary engineering in Ni–Cr–Fe B Bian, S Taheriniya, GM Muralikrishna, S Sen, C Gammer, I Steinbach, ... Acta Materialia 264, 119602 , 2024 2024 Citations: 17
Grain boundary diffusion and segregation of Cr in Ni Σ11 (1̄13)[110] bicrystals: Decoding the role of grain boundary defects SV Sevlikar, GM Muralikrishna, D Gaertner, S Starikov, T Brink, ... Acta Materialia 278, 120229 , 2024 2024 Citations: 16
Atomic transport in B2-ordered Al (Fe, Ni) alloys: Tracer-interdiffusion couple approach GM Muralikrishna, VA Esin, KN Kulkarni, BS Murty, G Wilde, SV Divinski Intermetallics 126, 106920 , 2020 2020 Citations: 16
Grain-and interphase boundary diffusion in eutectic AlCoCrFeNi2. 1 compositionally complex alloy H Zhang, GM Muralikrishna, A Akbari, H Rösner, BJ Tyler, SV Divinski, ... Acta Materialia 294, 121082 , 2025 2025 Citations: 15
Kinetic and structural insights into the grain boundary phase transitions in Ni-Bi alloys B Bian, S Taheriniya, GM Muralikrishna, A Godha, SK Makineni, ... Acta Materialia 245, 118632 , 2023 2023 Citations: 14
Preparation of nanocrystalline nickel oxide from nickel hydroxide using spark plasma sintering and inverse Hall-Petch related densification MB Ponnuchamy, GM Muralikrishna, VR Mannava, GS Reddy Ceramics International 44 (13), 15019-15023 , 2018 2018 Citations: 12
Demystifying the semiconductor‐to‐metal transition in amorphous vanadium pentoxide: the role of substrate/thin film interfaces ACM Esther, GM Muralikrishna, M Chirumamilla, MS Pinto, S Ostendorp, ... Advanced functional materials 34 (30), 2309544 , 2024 2024 Citations: 9
Microstructure stability and self-diffusion in the equiatomic HfScTiZr HCP multi-principal element alloy GM Muralikrishna, S Sen, SK Ayyappan, S Sankaran, K Guruvidyathri, ... Journal of Alloys and Compounds 976, 173196 , 2024 2024 Citations: 8