Severe plastic deformation and subsequent heat treatments yield nanostructured commercially pure (CP) titanium Grade 4 with average grain size of about 100 nm and exceptional strength. To elucidate the underlying strengthening mechanisms in this nano...
The formation of Zn and Mg segregations at a tilt Σ5{013} <100> grain boundary (GB) in Al and the effects of these solutes on deformation behavior of polycrystalline Al were investigated using ab initio total energy calculations. Using a step-b...
Using Molecular Dynamics (MD) and Monte Carlo (MC) simulations, we studied the grain boundary (GB) segregation under different temperatures and Cr concentrations in Ni-Cr alloys with two distinct grain-boundary structures, i.e., Σ5(310)[010] an...
Chemical composition of interfaces—free surfaces and grain boundaries—is generally described by the Langmuir–McLean segregation isotherm controlled by Gibbs energy of segregation. Various components of the Gibbs energy of segregation, the standard an...
The role of entropy in materials science is demonstrated in this report in order to establish its importance for the example of solute segregation at the grain boundaries of bcc iron. We show that substantial differences in grain boundary chemistry a...
Several grain sizes were obtained by heat treatment at different temperatures for interstitial-free (IF) and 2.25Cr-1Mo steels. Samples of the steels with different grain sizes were aged at 600 and 680 °C for IF steel and 520 and 560 °C for 2.25Cr-1M...
The question is formulated as to whether entropy-driven grain boundary segregation can exist. Such a phenomenon would be based on the assumption that a solute can segregate at the grain boundary sites that exhibit positive segregation energy (enthalp...
There are two sources of quantitative data on grain boundary segregation: careful experimental results and calculated data. These values can be compared in various ways. Here we show a comparison of average concentrations of silicon, vanadium, and ti...
In austenitic steels, the co-segregation of C and Cr at grain boundaries can result in the formation of Cr23C6. However, the addition of B to steels can effectively reduce the amount of Cr23C6 formed and inhibit its ripening in experiments, simultane...
Grain boundary solute segregation is becoming increasingly common as a means of stabilizing nanocrystalline alloys. Thermodynamic models for grain boundary segregation have recently revealed the need for spectral information, i.e., the full distribut...
The atomistic structure and point-defect thermodynamics of the model
The study of the effects of impurity on grain boundaries is a critical aspect of materials science, particularly when it comes to understanding and controlling the properties of materials for specific applications. One of the related key issues is th...
Addition of B is beneficial for the hardenability of low-alloy steels and the effect is further improved when combined with the addition of Mo. While experiments demonstrated that Mo reduces the M23(C,B)6 precipitation and indicated an interaction be...
The segregation of P and S to grain boundaries (GBs) in fcc Cu has implications in diverse physical-chemical properties of the material and this can be of particular high relevance when the material is employed in high performance applications. Here,...
Grain boundary (GB) segregation is an important phenomenon that affects many physical properties, as well as microstructure of polycrystals. The segregation of solute atoms on GBs and its effect on GB structure in Al were investigated using two appro...
The segregation of solute atoms at grain boundary (GB) has an important effect on the GB characteristics and the properties of materials. The study of multielement co-segregation in GBs is still in progress and deserves further research at the atomic...
A phase-field model for the precipitation of Fe-Cr-Al alloy is established incorporating grain boundary (GB) effects and irradiation-accelerated diffusion. The radiation source and grain boundary effect are incorporated to broaden the applicability o...
This work presents a comprehensive and detailed ab initio study of interactions between the tilt Σ5(210) grain boundary (GB), impurities X (X = Al, Si) and vacancies (Va) in ferromagnetic fcc nickel. To obtain reliable results, two methods of s...
A theoretical two-dimensional (2D) model is proposed that describes the effect of grain boundary (GB) segregations on the fracture toughness of nanocrystalline or ultrafine-grained alloys. It is shown that GB segregations can lead to crack curvature,...
In the present work, atomistic modeling based on the quasiparticle approach (QA) was performed to establish general trends in the segregation of solutes with different atomic size at symmetric ⟨100⟩ tilt grain boundaries (GBs) in α-Fe. Three types of...
Phosphorus atoms in steels accumulate at grain boundaries via thermal and irradiation effects and induce grain boundary embrittlement, which is experimentally confirmed by an increase in the ductile-brittle transition temperature. Quantitative predic...
Segregation of rare earth alloying elements are known to segregate to grain boundaries in Mg and suppress grain boundary sliding via strong chemical bonds. Segregation of Mn, however, has recently been found to enhance grain boundary sliding in Mg, t...
Hydrogen enhanced decohesion is expected to play a major role in ferritic steels, especially at grain boundaries. Here, we address the effects of some common alloying elements C, V, Cr, and Mn on the H segregation behaviour and the decohesion mechani...
In order to investigate the effect of Mg addition on the embrittlement of Cr-Mo steels, the 2.25Cr1Mo steel plates containing Mg, P contents were refined with vacuum induction furnace and rolled with double-stick reversible rolling mill. The impact t...
A series of Cu-Zr nanocrystalline alloy films with varying Zr contents were fabricated via magnetron co-sputtering technology. The effect of Zr content on the microstructure and mechanical properties of the alloy films was investigated, and the stren...
The intermediate-temperature embrittlement range was examined for Fe, Al, Cu, and Ni alloys. It was found that this embrittlement occurs in many alloys, although the causes are very diverse. Embrittlement can be due to fine matrix precipitation, prec...
The last two decades have witnessed significant progress in the development of severe plastic deformation techniques to produce ultrafine-grained materials with new and superior properties. This review examines works and achievements related to the l...
Fiber welding of socket-joints made of nanostructured high-performance molybdenum alloy (NS Mo) was carried out to get a better understanding of the role of welding heat input. It was found that low heat input (i.e., high welding speed) resulted in s...
An ultrafine-grained (UFG) Al–Cu–Mg alloy (AA2024) was produced by surface mechanical grinding treatment (SMGT) with a high strain rate, and the precipitation behavior inside the grain and at the grain boundary was investigated. During SM...
The simulation welding thermal cycle technique was employed to generate different sizes of prior austenite grains. Dilatometry tests, in situ laser scanning confocal microscopy, and transmission electron microscopy were used to investigate the role o...
Hydrogen embrittlement, which severely affects structural materials such as steel, comprises several mechanisms at the atomic level. One of them is hydrogen enhanced decohesion (HEDE), the phenomenon of H accumulation between cleavage planes, where i...
Microscopic phase-field chemomechanics (MPFCM) is employed in the current work to model solute segregation, dislocation-solute interaction, spinodal decomposition, and precipitate formation, at straight dislocations and configurations of these in a m...
A molecular dynamics (MD) simulation method is used to investigate the effect of grain boundary (GB) segregation on the deformation behavior of bicrystals of equiatomic nanoscale CoCrCuFeNi high-entropy alloy (HEA). The deformation mechanisms during...
Transmission electron microscopy (TEM), second ion mass spectrum (SIMS) and atom probe tomography (APT) techniques are used to study the Li ion distribution in the oxide formed on the rolling surface (SN) of Zircaloy-4 corroded in lithiated water wit...
Exploring structural effects that influence both the mechanics and magnetism in nanocrystalline materials, particularly extremely-fine nanograined ones with grain sizes down to several nanometers, is of high interest for developing multifunctional ma...
The analysis of grain boundary (GB) diffusion in metallic systems based on Cu, Ni, Ag and Al was made to set demonstrate the common behavior. It was shown that the slow penetration for 11 systems can be connected with negative segregation or specific...
Solutes segregating at the grain boundary (GB) have a significant influence on the mechanical and chemical properties of steel. In this study, the segregation effects of Si, P, and S on γ-Fe ∑5 (210)[001] GB were systematically analyzed wit...
Advanced SA508-4N RPV steel samples, unadded, P-added, and P+Ce-added, are investigated on their hot ductility behavior. Hot tensile tests are carried out in the temperature range of 750 to 1000 °C through a Gleeble 1500D machine. It is demonstra...
The effect of hydrogen atoms at grain boundaries in metals is usually detrimental to the cohesion of the interface. This effect can be quantified in terms of the strengthening energy, which is obtained following the thermodynamic model of Rice and Wa...
The high temperature creep properties of three groups of modified 9Cr-1Mo steel samples, undoped, doped with Sb, and doped with Sb and Ce, are evaluated under the applied stresses from 150 MPa to 210 MPa and at the temperatures from 873–923 K. The cr...
The peculiarities of Ni and Fe diffusion in polycrystalline Cu and Cu-Fe alloys at a 650–750 °C temperature range were studied. It was shown that the bulk diffusion coefficients were in a good agreement with the available literature data ob...
This work investigates the influence of chemical composition, grain boundary (GB) type, and atomic distribution on the thermal conductivity of Hf–Nb–Ta–Zr refractory high-entropy alloys (RHEAs) via atomistic simulations. Three compo...
The recycling of steel scrap is becoming more and more developed to save resources and protect the environment. However, impurities such as antimony in steel scrap cannot be economically and effectively removed, resulting in an inevitable accumulatio...
This study investigated the influence of phosphorus (P) addition on the stress rupture properties of direct aged IN706 superalloy. The results showed that P slightly improved the stress rupture life of the superalloy when added in the range between 0...
In order to reduce the segregation of Cr and Mo and inhibit the precipitates, we added a small amount of B and Ce to traditional S31254 steel. Using an air-cooling and low-temperature diffusion treatment, the purpose was to control B and Ce at the gr...
Based on molecular dynamics simulations, the creep behaviors of nanocrystalline Ni before and after the segregation of Mo atoms at grain boundaries are comparatively investigated with the influences of external stress, grain size, temperature, and th...
The composition of grain boundaries (GBs) determines their mechanical behavior, which in turn affects the mechanical properties of nanocrystalline materials. Inspired by GB segregation and the concept of high-entropy alloys (HEAs), we investigated, r...
Dense metal membranes that are based on palladium (Pd) are promising for hydrogen separation and production due to their high selectivity and permeability. Optimization of alloy composition has normally focused on bulk properties, but there is growin...
Press hardening steel (PHS) is widely applied in current automotive body design. The trend of using PHS grades with strengths above 1500 MPa raises concerns about sensitivity to hydrogen embrittlement. This study investigates the hydrogen delayed fra...
The influence of alloying elements on the cohesive strength of metal heat-resistant alloys (HRAs) is analyzed. Special parameters are introduced to characterize the individual contribution of each alloying element. These are the partial molar cohesio...
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