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The formation of iron (Fe)‐containing intermetallics during solidification is challenging due to the influences of cooling rate and chemical composition. Differential scanning calorimetry (DSC) is an accurate analysis method but merely replicates adjustable cooling conditions. Thereby, the solidification range is traversed several times before DSC measurement. For this purpose, thermal analysis cooling curves with double thermocouple are conducted to investigate the formation temperature of Fe‐rich intermetallics in different AlSi casting alloys. In addition, the influence of chemical composition is examined by increasing the initial contents of iron, manganese, and chromium to 0.8 wt% each. The double thermocouple setup allows determining feeding points and solid fractions of the alloy compounds. To evaluate the data sets, the statistical program R is used to improve data processing and smoothing. The signature of Fe‐rich intermetallics in the temperature–time plots corresponds to the detected phases in optical micrographs. In addition, scanning electron microscopy with energy‐dispersive spectroscopy and electron backscattering diffraction are used to measure the local chemical composition and identify the iron‐rich intermetallics. Real‐time evaluation (differential calculation, first derivative, incl. smoothing) for an applicable filtration process can be performed using thermocouples with analog‐to‐digital converter and Python programs with an interactive graphical interface. [ABSTRACT FROM AUTHOR]

The aim of the work has been to analyze the aluminum alloys for plastic working from the point of view of their usefulness in the new hybrid manufacturing process which includes gravity casting and forging. The tests have been carried out on popular aluminum alloys from the 2xxx and 7xxx series: 2017A, 2024, 7022, and 7075, respectively. The authors have focused on the problem of using these materials at the casting stage. The analyses have included verification of the technological properties of alloys, including fluidity and the tendency to create porosities. Next, the influence of the solidification rate (associated with the use of various molds) on the casting microstructure has been determined. Based on the conducted analyzes, the alloys with the best casting behavior have been indicated. At the same time, possible problems that may occur at the forging stage have been discussed. [ABSTRACT FROM AUTHOR]

The paper concerns double high-zinc aluminium alloys inoculated with master alloys containing titan and comprises research on the influence of inoculation on grain refinement. Most aluminium alloys before being cast have relatively low strength properties and therefore a series of treatments are applied in order to improve these properties. One of the treatments is the grain fragmentation process, called grain refinement treatment that allows to improve material properties of alloy, improve the feeding properties during the casting solidification, as well as to obtain more robust machinability of casting. Al alloy with 20wt% Zn (AlZn20) was tested, inoculated with the addition of traditional master alloy AlTi3C0.15 before casting to the sand mould. The results obtained during the studies show nucleating activity of the master alloy, proved by reduced overcooling and recalescence on cooling curves. Additionally, the role of titanium in this process is explained. [ABSTRACT FROM AUTHOR]

The aim of this work is the development of the lattice Boltzmann model for simulation of the mold filling process. The authors present a simplified approach to the modeling of liquid metal-gas flows with particular emphasis on the interactions between these phases. The boundary condition for momentum transfer of the moving free surface to the gaseous phase is shown. Simultaneously, the method for modeling influence of gas back pressure on a position and shape of the interfacial boundary is explained in details. The problem of the lattice Boltzmann method (LBM) stability is also analyzed. Since large differences in viscosity of both fluids are a source of the model instability, the so-called fractional step (FS) method allowing to improve the computation stability is applied. The presented solution is verified on the bases of the available reference data and the results of experiments. It is shown that the model describes properly such effects as: gas bubbles formation and air back pressure, accompanying liquid-gas flows in the casting mold. At the same time the proposed approach is easy to be implemented and characterized by a lower demand of operating memory as compared to typical LBM models of two-phase flows. [ABSTRACT FROM AUTHOR]

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