Bond nature between reinforcing phase and matrix in cast composite material of [Al – FeCr] system and reinforcement mechanism of cast Al-alloys obtained using Lost-foam casting process

Abstract

Samples of zero-dimensional cast composite material of [Al – FeCr] system were obtained by inoculating aluminum cast alloy grade AK12 by DSTU 2839:1994 (hereinafter –AK12) with dispersed intermetallic compound FeCr in the “cavity” of evaporative casting model. The chemical composition of structural components of composite castings was determined before and after the reinforcement process by the X-ray spectral microanalysis. The results of X-ray spectral microanalysis showed that the chemical composition of the intermetallic reinforcing phase and the aluminum matrix of the zero-dimensional cast composite material of [Al – FeCr] system practically does not differ from the chemical composition of its original components, that is, the material of the dispersed inoculator and aluminum casting alloy grade AK12. Machining of an experimental batch of castings and their further production tests confirmed the preliminary conclusions on the quality of composite castings based on the results of metallographic analysis and X-ray spectral microanalysis. Metal cutting showed that the intermetallic compound of the experimental composite isn’t chipping from the soft aluminum matrix of the zero-dimensional cast composite material of [Al – FeCr] system and therefore it can be assumed that there is an adhesive bond between the structural components of the experimental composite casting. The graphical interpretation and a mathematical treatment of experimental data made it possible to find out that the intermetallic compound and the aluminum matrix of the composite casting do not react with each other. Using the aluminium alloy grade AK12 as an example helped us to reveal the process mechanism of reinforcing aluminum casting alloys using dispersion-filled evaporative casting model.