Article
Materials Science, Multidisciplinary
Zizheng Song, Ranming Niu, Xiangyuan Cui, Elena V. Bobruk, Maxim Yu. Murashkin, Nariman A. Enikeev, Ji Gu, Min Song, Vijay Bhatia, Simon P. Ringer, Ruslan Z. Valiev, Xiaozhou Liao
Summary: Superplastic deformation of polycrystalline materials is usually achieved by diffusion-assisted grain boundary sliding at high temperatures. Recent research has shown that room-temperature superplasticity can be achieved in ultrafine-grained Al-Zn based alloys, but the underlying mechanism is still unclear. This study utilized in-situ tensile straining, electron microscopy characterization, and atomistic density functional theory simulation to reveal that the superplasticity at room temperature is achieved by grain boundary sliding and grain rotation, facilitated by the continuous diffusion of Zn. The diffusion of Zn atoms from grains to grain boundaries forms a Zn nanolayer, acting as a solid lubricant to lower the energy barrier of grain boundary sliding.
Article
Nanoscience & Nanotechnology
Anastasia V. Mikhaylovskaya, Olga A. Yakovtseva, Natalia Yu. Tabachkova, Terence G. Langdon
Summary: During superplastic deformation of microduplex-structured brasses, strain primarily occurs in the beta-phase through grain boundary sliding and dislocation slip/creep mechanisms. Dynamic recrystallization and twinning transform the initial coarse beta-phase grains into ultrafine grains, and alloying with Al improves superplastic behavior and reduces residual cavitation.
SCRIPTA MATERIALIA
(2022)
Article
Chemistry, Physical
Anastasia V. Mikhaylovskaya, Olga A. Yakovtseva, Andrey G. Mochugovskiy, Joan Cifre, Igor S. Golovin
Summary: The influence of a minor addition of Zn on the superplastic properties of Al-Mg alloys was investigated. It was found that the addition of a small amount of Zn can promote grain boundary sliding, resulting in increased strain rate sensitivity and elongation-to-failure of the alloy.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Qing Zhang, Xiaofei Ju, Jun Liu, Lei Wang, Yang Li, Haowei Wang, Zhe Chen
Summary: The addition of TiB2 nanoparticles as reinforcement in Al-Zn-Mg-Cu composite leads to the formation of fine-equiaxed grains, which enhances both the elongation and thermal stability of the material. The deformation at grain boundaries is controlled by grain boundary sliding mechanism, and the stress release and prevention of cavitation are facilitated by locally melted Mg-rich phases.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
Jie Feng, Lianpeng Zhang, Yufeng Zhang, Guizhen Feng, Chen Wang, Wenbin Fang
Summary: Multi-pass rolling can improve the strength and ductility synergy in ultrafine-grained AZQ310 alloy sheet by reducing grain boundary segregation. The as-extruded alloy has high yield strength but poor elongation due to the presence of ultra-fine grains and co-segregation of Al/Zn atoms at grain boundaries. In contrast, after multi-pass rolling, the sheet exhibits higher yield and ultimate strength, as well as improved elongation along the rolling direction.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Nanoscience & Nanotechnology
Jiwei Geng, Yugang Li, Hongyu Xiao, Zhiping Wang, Mingliang Wang, Dong Chen, Haowei Wang
Summary: The microstructural evolution and damage mechanisms near the fatigue crack tip in a TiB2/Al composite were investigated, revealing the formation of micro deformation bands and ultrafine grains. The study also highlighted the role of TiB2 particles in impeding the propagation of deformation bands and influencing crack growth.
SCRIPTA MATERIALIA
(2021)
Article
Chemistry, Physical
Anushree Dutta, Jayanta Das
Summary: The oxidation behavior of (Ni0.92Zr0.08)(100)Al--x(x) ultrafine eutectic composites was systematically investigated at temperatures ranging from 500 to 900 degrees C. The addition of Al was found to enhance the oxidation resistance of the composites by refining the lamellae thickness and decreasing the mass gain.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Energy & Fuels
Siwat Linjee, Suphitcha Moonngam, Pitichon Klomjit, Namurata Sathirachinda Palsson, Chaiyasit Banjongprasert
Summary: This research focuses on the effects of alloying elements (Zn, In) and grain size reduction on the electrochemical behaviors of aluminium alloy anodes. The results show that zinc and indium can improve the stability and activation of ion dissolution, respectively, while grain size reduction can enhance the anode life in alkaline solution.
Article
Materials Science, Multidisciplinary
Chuanlai Liu, Alistair Garner, Huan Zhao, Philip B. Prangnell, Baptiste Gault, Dierk Raabe, Pratheek Shanthraj
Summary: The incorporation of CALPHAD database into a phase-field framework successfully simulated the complex kinetics of non-equilibrium grain boundary microstructures in high-strength Al-Zn-Mg-Cu alloys, which is crucial for understanding the quenching process of the alloys.
Article
Chemistry, Physical
Igor C. dos Santos, Eric M. Mazzer, Roberto B. Figueiredo, Terence G. Langdon, Pedro Henrique R. Pereira
Summary: Experiments were conducted to investigate the microstructural evolution of an Al-5.7Zn-1.8Mg-2.1Cu alloy subjected to torsional straining. The material exhibited two consecutive hardening stages during high-pressure torsion (HPT) processing. The first stage involved the accumulation and rearrangement of dislocations, resulting in the formation of fine cells/subgrains. The second stage involved the fragmentation of second phase particles and the development of highly elongated grains.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Metallurgy & Metallurgical Engineering
Supriya Nandy, Shao-Pu Tsai, Leigh Stephenson, Dierk Raabe, Stefan Zaefferer
Summary: This study investigates the quantitative roles of Ca, Al, and Zn in improving the ductility of Mg alloys, with a focus on the synergistic effects of Ca and Zn. The results show that the balanced influence of reduced slip anisotropy and increased grain boundary cohesion can design high strength and high ductility rare-earth free Mg alloy. The addition of Ca, Zn, and Al have different effects on the alloy's performance, and the balanced effects contribute to improved strength and ductility.
JOURNAL OF MAGNESIUM AND ALLOYS
(2021)
Article
Materials Science, Multidisciplinary
Yiming Zhong, Bo Zhang, Ling Fang, Junjie Chen, Wei Xu, Xiuyan Li
Summary: Grain refinement through severe plastic deformation (SPD) usually leads to strain softening in Al-Zn supersaturated solid solution. However, in this study, by cryogenic high-pressure torsion, a single-phase supersaturated solid solution nanostructure with relaxed grain boundaries was successfully achieved in Al-21.7 at% Zn alloy, resulting in giant hardening instead of softening. The nanocrystalline Al-Zn alloy with a grain size of 15 nm exhibits an ultrahigh yield strength of approximately 642 MPa.
MATERIALS RESEARCH LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Zhiping Wang, Hongyu Xiao, Wei Chen, Yugang Li, Jiwei Geng, Keneng Li, Peikang Xia, Mingliang Wang, Xianfeng Li, Dong Chen, Haowei Wang
Summary: The dependence of grain boundary structure on precipitation at grain boundaries (GBs) in a TiB2/Al-Zn-Mg-Cu composite has been systematically investigated. It was found that the average size and coverage of grain boundary precipitates (GBPs) increase while the number density decreases with the increasing misorientation of low angle GBs (LAGBs). For high angle GBs (HAGBs), the coincidence site lattice (CSL) GBs and TiB2 particles have an effect on GBPs. The results indicate that TiB2 particles promote the nucleation of GBPs while limiting their growth.
MATERIALS CHARACTERIZATION
(2023)
Article
Materials Science, Multidisciplinary
Andrey Kuznetsov, Lidia Karkina, Yuri Gornostyrev, Pavel Korzhavyi
Summary: In Al, Zn tends to form a thick segregation layer at grain boundaries, while Mg forms an atomically thin segregation layer. The segregation of Zn decreases the barriers for grain boundary sliding, while the segregation of Mg increases them. These results demonstrate a strong relationship between the chemical bonding of solute atoms, their segregation ability, and grain boundary strength.
Article
Nanoscience & Nanotechnology
B. Wang, W. Xu, X. Zhou, X. Y. Li, J. S. Qiao
Summary: Equiaxial-nanograined pure aluminum with an average grain size of 65 nm was successfully fabricated through the combined plastic deformation process of cold rolling and cryogenic high pressure torsion. The aluminum exhibited high strength and superior thermal stability, mainly due to the presence of high angle grain boundaries and grain boundary relaxation.
SCRIPTA MATERIALIA
(2021)
Article
Materials Science, Multidisciplinary
Sylwia Rzepa, Zuzanka Trojanova, Jan Dzugan, Ruslan Z. Valiev, Martina Koukolikova, Daniel Melzer, Michal Brazda
Summary: Additive manufacturing (AM) allows faster and cheaper production of complex-shaped parts. Equal channel angular pressing (ECAP) induces strain and dislocations, leading to material strengthening. This study investigates the combination of directed energy deposition (DED) and ECAP processing on titanium alloy Ti-6Al-4V. The ECAP-processed specimens show significant improvement in mechanical properties.
MATERIALS CHARACTERIZATION
(2023)
Article
Materials Science, Multidisciplinary
Yulin Chen, Manping Liu, Lipeng Ding, Zhihong Jia, Shuangfeng Jia, Jianbo Wang, Maxim Murashkin, Ruslan Z. Valiev, Hans J. Roven
Summary: In this study, non-uniform Mg solute distribution (i.e., Mg-enriched/depletion zones) around grain boundaries (GBs) in a nanocrystalline Al-8 Mg alloy was observed through experimental observation. The abnormal segregation hindered GB migration and dislocation motion, thus enhancing the strength of the material. A proposed inhomogeneous solute distribution mechanism may contribute to the development of new strengthening mechanisms for nanocrystalline materials.
MATERIALS CHARACTERIZATION
(2023)
Article
Materials Science, Multidisciplinary
Daniel Olasz, Gyorgy Safran, Noemi Szasz, Gabriella Huhn, Nguyen Quang Chinh
Summary: This study investigated AlCu thin films representing the whole composition range using multiple experimental methods. It was found that the films exhibited exceptionally high hardness in the middle concentration range of 40-70 at% Cu. Furthermore, the grain boundary sliding deformation mechanism and highly precipitated microstructure of the films also influenced the indentation size effect.
Article
Nanoscience & Nanotechnology
Nguyen Q. Chinh, Daniel Olasz, Anwar Q. Ahmed, Gyorgy Safran, Janos Lendvai, Terence G. Langdon
Summary: Experimental data show that the conventional Hall-Petch relationship is not applicable to metals with submicrometer structures. A new dislocation model is proposed to modify the Hall-Petch relationship and provide a uniform description of grain size strengthening in submicron-structured f.c.c. metals and solid solution alloys.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Chemistry, Physical
Elena V. Bobruk, Maxim Yu. Murashkin, Ilnar A. Ramazanov, Vil U. Kazykhanov, Ruslan Z. Valiev
Summary: This study aims to achieve superplasticity of ultrafine-grained (UFG) Al 2024 alloy at temperatures lower than traditional commercial Al alloys. Complex tensile tests were conducted at various temperatures and strain rates, and the UFG alloy exhibited superplastic behavior at 240 and 270 degrees C. The UFG alloy also demonstrated higher strength compared to the standard strengthening heat treatment T6.
Article
Materials Science, Multidisciplinary
Andrew K. Hoffman, Yongfeng Zhang, Maalavan Arivu, Li He, Kumar Sridharan, Yaqiao Wu, Rinat K. Islamgaliev, Ruslan Z. Valiev, Haiming Wen
Summary: In nuclear reactor environments, nanocrystalline 304 stainless steel exhibits unique radiation-induced segregation behavior with the enrichment of Cr at grain boundaries. Lattice-based atomic kinetic Monte Carlo simulations reveal the influences of grain size, injected interstitials, and self-ion injection on grain boundary segregation.
Article
Mechanics
G. V. Klevtsov, L. R. Botvina, N. A. Klevtsova, R. Z. Valiev, I. N. Pigaleva
Summary: Fatigue failure is the most common type of failure in various engineering systems, and its study is crucial for predicting system's service life. The investigation of fatigue failure in new ultrafine-grained nanostructured metal materials is particularly interesting. This study demonstrates the possibility of determining the maximum cycle stress and cycle asymmetry coefficient from the depth of plastic zones beneath the surface of fatigue fractures.
PHYSICAL MESOMECHANICS
(2023)
Review
Chemistry, Physical
Gyoergy Safran, Peter Petrik, Noemi Szasz, Daniel Olasz, Nguyen Quang Chinh, Miklos Serenyi
Summary: By scaling up the substrate size and utilizing the micro-combinatorial technique, the properties of multicomponent thin films as a function of their composition were comprehensively studied. Various characterization techniques were employed to analyze the films, enabling greater detail and efficiency in their characterization.
Article
Chemistry, Physical
Otto Temesi, Lajos K. Varga, Xiaoqing Li, Levente Vitos, Nguyen Q. Chinh
Summary: The relationship between rigidity (measured by shear modulus, G) and hardness (measured by Vickers hardness, HV) of early transition metal (ETM)-based refractory high-entropy alloys (RHEA) and bond parameters (valence electron concentration, VEC, and enthalpy of mixing, ΔH-mix) was investigated. The study found a close correlation between the G and HV characteristics and the bonding parameters. The room temperature values of G and HV increase with higher VEC and more negative ΔH-mix. Equations were derived for the first time through multiple linear regression analysis to aid in designing the mechanical properties of ETM refractory high-entropy alloys.
Article
Materials Science, Multidisciplinary
Gennadiy V. Klevtsov, Ruslan Z. Valiev, Natal'ya A. Klevtsova, Maksim N. Tyurkov, Irina N. Pigaleva, Denis A. Aksenov
Summary: This paper analyzes the fracture kinetics and mechanisms of different ultrafine-grained materials with different crystal lattices in the low-cycle fatigue region. The tests conducted show that the formation of ultrafine-grained structure has an unclear effect on the total number of cycles to failure of the samples. The fatigue crack initiation cycles account for about 20% of the total life of the samples, regardless of the material state and crystal lattice type. The fatigue crack propagation rates of the majority of investigated ultrafine-grained materials are close to or lower than that of the initial coarse-grained materials.
Article
Crystallography
Shivam Dangwal, Kaveh Edalati, Ruslan Z. Z. Valiev, Terence G. G. Langdon
Summary: Strengthening and softening mechanisms in ultrafine-grained materials have been debated for many years. This study examines the Hall-Petch relationship in ultrafine-grained magnesium, aluminum, copper, and iron. The results show that while the materials follow the Hall-Petch relationship initially, an up-break occurs for grain sizes below 500-1000 nm. This is due to enhanced dislocation contribution. However, a down-break occurs for grain sizes smaller than 70-150 nm due to diminished dislocation contribution and increased thermally-activated phenomena. The study also finds that strategies other than grain refinement, such as microstructural stabilization by segregation or precipitation, are necessary to achieve extra strengthening.
Article
Materials Science, Multidisciplinary
Roman R. Valiev, Alexey V. Panin, Emil I. Usmanov, Yana N. Savina, Ruslan Z. Valiev
Summary: This study demonstrates for the first time the influence of high-pressure torsion (HPT) on microstructural refinement and mechanical strength of Ti-6Al-4V titanium alloy produced by wire-feed electron-beam additive manufacturing. HPT processing results in an ultrafine-grained (UFG) structure and significantly increases the microhardness of the alloy. Microscopic studies reveal that the UFG structure consists predominantly of alpha and beta phases.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Chemistry, Physical
Anwar Qasim Ahmed, Daniel Olasz, Elena V. Bobruk, Ruslan Z. Valiev, Nguyen Q. Chinh
Summary: A supersaturated Al-Zn-Mg-Zr alloy with ultrafine-grained structure was obtained through the ECAP technique, resulting in significantly improved hardness and changes in subsequent thermal processes.
Article
Materials Science, Biomaterials
Alexander A. Matchin, Evgeniy V. Nosov, Alexander A. Stadnikov, Gennadiy V. Klevtsov, Luiza R. Rezyapova, Natalia A. Sayapina, Elena V. Blinova, Ruslan Z. Valiev
Summary: This study focuses on the osseointegration behavior of medical implants made from nanostructured grade 4 titanium in maxillofacial surgery. The results show that nanotitanium implants have a significantly faster fixation rate due to osseointegration compared to standard factory-made implants, indicating better osseointegration for nanotitanium implants.
ACS BIOMATERIALS SCIENCE & ENGINEERING
(2023)
