The paper reports the results of a physical modelling study of the production of a hypereutectic aluminium alloy to be used for making an alloy vapour source for operation in the magnetron. Within the study, targets from a hypereutectic aluminium-silicon alloy were made in laboratory conditions. Thus obtained material was subjected to heat treatment, porosity analysis, and the assessment of the microstructure and fitness for being used in the magnetron. The process of melting the hypereutectic Al-Si alloy was carried out at the Department of Foundry of the Czestochowa University of Technology. The investigation into the production of the alloy vapour source for the synthesis of the dielectric material from the hypereutectic aluminium alloy has confirmed.
The paper, which is a summary and supplement of previous works and research, presents the results of numerical and physical modeling of the GX2CrNiMoCuN25-6-3 duplex cast steel thin-walled castings production. To obtain thin-walled castings with wall in the thinnest place even below 1 mm was used the centrifugal casting technology and gravity casting. The analyzed technology (centrifugal casting) enables making elements with high surface quality with reduced consumption of batch materials and, as a result, reducing the costs of making a unitary casting. The idea behind the production of cast steel with the use of centrifugal technology was to find a remedy for the problems associated with unsatisfactory castability of the tested alloy.
The technological evaluation of the cast construction was carried out using the Nova Flow & Solid CV 4.3r8 software. Numerical simulations of crystallization and cooling were carried out for a casting without a gating system and sinkhead located in a mold in accordance with the pouring position. It was assumed that the analyzed cast will be made in the sand form with dimensions 250×250×120 mm.
The work deals with the influence of change in the filling conditions of the ceramic moulds with plaster binder on the presence of gaseous
porosity and the microstructure of the achieved test castings with graded wall thickness. Castings made of EN AC-44000 alloy, produced
either by gravity casting, or by gravity casting with negative pressure generated around the mould (according to the Vacumetal
technology), or by counter-gravity casting were compared. The results of examinations concerning the density of the produced castings
indicate that no significant change in porosity was found. The increased size of silicon crystals was found for the increased wall
thicknesses due to the slower cooling and solidification of castings.
The performed examinations concerning the process of filling the plaster ceramic moulds with aluminium alloys allowed to assess the
influence of various methods of introducing the metal into the mould cavity on the macro- and microstructure of the obtained experimental
castings. The comparison was performed for castings with graded wall thickness made either of EN AC-44000 alloy or of EN AC-46000
alloy, produced either by gravity casting, or by gravity casting with negative pressure generated around the mould (according to the
Vacumetal technology), or by counter-gravity casting. It was found that the silicon crystals grow in size with an increase in wall thickness
due to the slower cooling and solidification of castings.