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  • Item type:Journal Issue,
  • Item type:Journal Issue,
    Computer Methods in Materials Science
    2025 - Vol. 25 - No. 4
  • Item type:Article, Access status: Open Access ,
    Full-field approaches for austenite-ferrite phase transformation simulations
    (Wydawnictwa AGH, 2025) Wermiński, Mariusz; Sitko, Mateusz; Madej, Łukasz
    Understanding the local evolution of phase transformations in steels, particularly the γ (austenite) → α (ferrite) transformation, is crucial for controlling the microstructure and properties of steel components. Over recent decades, significant progress has been made in the numerical modeling of this complex phenomenon. This development has been driven by both scientific curiosity and industrial needs, especially in processes such as hot rolling, forging, thermal treatment, etc. The developed models have evolved from simple solutions based on local equilibrium to more complex approaches that consider local heterogeneities. Modern computational approaches, such as Phase-Field (PF), Level-Set (LS), Cellular Automata (CA), Monte Carlo (MC) or Vertex based simulations, allow for the precise reproduction of microstructural evolution considering local instabilities. They also enable the analysis of phase boundary motion in an explicit manner. These techniques also allow for direct integration with thermodynamic data and mechanical models, thereby better capturing the physical mechanisms of phase transformations, such as chemical composition, diffusion resistance, or the influence of deformation. An overview of the state of the art in this area is presented within the paper. The model’s concepts, assumptions, fundamental equations, advantages, limitations, and potential practical applications are summarized. Special attention is given to modeling the γ → α transformation by the Cellular Automata method. The importance of incorporating phenomena such as diffusion, nucleation, and growth is emphasized. The need for consistency between experimental results and simulations is also highlighted.
  • Item type:Article, Access status: Open Access ,
    High-fidelity modeling of interface crossing in the diffusion welding process at the polycrystalline scale
    (Wydawnictwa AGH, 2025) Godinot, Camille; Rigal, Emmanuel; Bernard, Frédéric; Emonot, Philippe; Frayssines, Pierre-Eric; Védie, Luc; Bernacki, Marc
    Controlling the microstructure of a diffusion welded interface is a critical point to ensure optimum mechanical properties and the homogeneity of the joint. Beyond the intimate contact formation between bonded parts studied in the literature, this article focuses on the grain boundary crossing of the interface during this process and its measurement. Following this perspective, a level-set method has been used for full-field microstructure simulations in 2D with various interface parameters. Two crossing measurement models have been formulated, tested and discussed over the simulations.
  • Item type:Article, Access status: Open Access ,
    The Influence of Modified Inorganic Binders Intended for 3D Printing on Selected Properties of Thermally Cured Moulding Sands – Conventionally and with Microwaves
    (AGH University Press, 2026) Halejcio, Dawid M.; Major-Gabryś, Katarzyna
    This study determined the impact of thermal curing on the basic properties of moulding compounds made with commercial inorganic binders and binders based on them, modified for use in 3D printing technology (Binder Jetting). Two inorganic binders based on sodium silicate and a binder based on aluminosilicates were tested. As part of the work, the parameters for thermal curing of the mixtures were selected: for curing in a dryer, the best properties were obtained for mixtures containing 2.0 p.p.w. of binder cured for 10 min at 160°C. In the case of microwave curing, the best properties were obtained for moulding sands containing 2.0 p.p.w. of binder cured for 6 min at a device power of 800 W. The tests showed that the basic properties of moulding compounds with binders developed on the basis of commercial binders for use in 3D printing technology, thermally cured in a dryer, do not differ significantly from the properties of compounds with commercial binders. In the case of microwave curing, a reduction in the strength of compounds with new binders was observed in relation to compounds with classic binders. Thermal deformation tests of compounds with classic and modified binders confirmed the typical behavior observed for inorganic systems. It was proven that new, modified inorganic binders developed for 3D printing of moulds and cores using Binder Jetting technology can be used as binding materials in thermally cured moulding sands. Both thermal curing methods were assessed as suitable for curing moulding compounds with new binders.
  • Item type:Article, Access status: Open Access ,
    Determination of the Heat Transfer Coefficient in the Isothermal Quenching Process of ADI Cast Iron Cooled with Water Mist
    (Akademia Górniczo-Hutnicza, 2026) Burbelko, Andriy A.; Stręk, Piotr
    Isothermal quenching of austempering cast iron (ADI) castings requires that, after austenitization the casting must be rapidly cooled to the temperature of isothermal austenite decomposition. The cooling rate throughout the entire volume of the heat-treated product must be high enough to prevent pearlitic transformation. At the same time, the temperature of the cooled surface must not decrease below the martensitic transformation start temperature Ms. The cooling rate of the casting surface is determined by factors such as the temperature difference between the surface of the cooled casting and the cooling medium, the thermal conductivity of cast iron, the heat transfer coefficient, and the wall thickness of the treated casting. In the case of cooling with water mist, the heat transfer coefficient depends on the temperature of the cooled surface. To control the cooling process of castings using water mist, information about this relationship for the temperature range of 200–800°C is needed. Available scientific publications on this subject contain contradictory data. Therefore, a measuring station was built with the ability to set the temperature of the cooled surface. The station includes a measuring system that allows the measurement of the heat flux flowing from the heating element into the environment. The result of the research is the measurement of the relationship between the temperature of the cooled surface and the heat transfer coefficient. The values obtained will be used in the future to build a numerical model of ADI castings heat treatment. This work may contribute to the future replacement of salt baths (currently used for fast cooling and austempering) with water mist spraying. In this case, the low-temperature operation of austenite decomposition can be performed without the use of salt a bath.
  • Item type:Article, Access status: Open Access ,
    Quaternionic Quantum Mechanics: the Particles, Their q-Potentials and Mathematical Electron Model
    (AGH University Press, 2026) Bożek, Bogusław; Danielewski, Marek; Sapa, Lucjan
    In this work we show the quaternionic quantum descriptions of physical processes from the Planck to macro scale. The results presented here are based on the concepts of the Cauchy continuum and the elementary cell at the Planck scale. The structurally symmetric quaternion relations and the postulate of the quaternion velocity have been important in the present development. The momentum of the expansion and compression $u̇_{0}(t, x)$ is the consequence of the scalar term $\sigma_{0}(t, x)$ in the quaternionic deformation potential. The quaternionic $G_{0}(m)(σ_{0} + \hat{\textstyle \phi} )$, vectorial $G_{0}(m) \hat{\textstyle \phi}$ and scalar $G_{0}(m)\sigma_{0}$ propagators are used to generate the second order PDE systems for the proton, electron and neutron. A mathematical model of an electron is formulated. It is described by the hyperbolic-elliptic partial differential system of quaternion equations with the initial-boundary conditions. The boundary conditions are generated by the quaternion energy flux that is found with the use of the Gauss theorem, the Cauchy–Riemann derivative and other mathematical formulas. The rigorous assessment of the second order PDE systems allows the proposal of two second order PDE systems for the $u$ and $d$ quarks from the up and down groups. It was verified that both the proton and the neutron obey experimental findings and are formed by three quarks. The proton and neutron are formed by the $d$-$u$-$u$ and $d$-$d$-$u$ complexes, respectively. The u and d quarks do not comply with the Cauchy equation of motion. The inconsistencies of the quarks’ PDE with the quaternion forms of the Cauchy equation of motion account for their short lifetime and the observed Quarks Chains. That is, they explain the Wilczek phenomenological paradox: Quarks are Born Free, but everywhere they are in Chains.
  • Item type:Journal Volume,
  • Item type:Journal Issue,
    Journal of Casting & Materials Engineering
    2026 - Vol. 10 - No. 1
Prawa dostępu

W uzgodnieniu z Wydawnictwami AGH od 1 marca 2011 r. pełne teksty artykułów zamieszczanych na łamach czasopism elektronicznych wydawanych w AGH dostępne są w sieciach rozległych bez żadnych ograniczeń.

Dostęp: otwarty
Licencja: CC BY 4.0 (Uznanie autorstwa 4.0 Międzynarodowe)