The research described in this contribution is focused on fractographic analysis of the fracture area of newly developed eutectic silumin type AlSi9NiCuMg0.5 (AA 4032), which was developed and patented by a team of staff of the Faculty of Mechanical Engineering. The paper presents determination of the cause of casting cracks in operating conditions. Fractographic analysis of the fracture area, identification of the structure of the casting, identification of structural components on the surface of the fracture surface and chemical analysis of the material in the area of refraction were performed within the experiment. Al-Si alloys with high specific strength, low density, and good castability are widely used in pressure-molded components for the automotive and aerospace industries. The results shown that the inter-media phases Fe-Al and Fe-Si in aluminium alloys lead to breakage across the entire casting section and a crack that crossed the entire cross section, which was confirmed by EDS analysis.
In the course of homogenizing annealing of aluminium alloys being cast continually or semi-continually it appears that chemical inhomogenity takes off within separate dendritic cells (crystal segregation). It is about a diffusion process that takes place at the temperature which approaches the liquid temperature of the material. In that process the transition of soluble intermetallic compounds and eutectic to solid solution occurs and it suppresses crystal segregation significantly . The temperature, homogenization time, the size of dendritic cells and diffusion length influences homogenizing process. The article explores the optimization of homogenizing process in terms of its time and homogenizing annealing temperature which influence mechanical properties of AlZn5,5Mg2,5Cu1,5 alloy.
This paper deals with the evaluation of the corrosion resistance of the Al-Si alloys alloyed with the different amount of antimony. Specifically it goes about the alloy AlSi7Mg0,3 which is antimony alloyed in the concentrations 0; 0,001; 0,005; 0,01 a 0,05 wt. % of antimony. The introduction of the paper is dedicated to the theory of the aluminium alloys corrosion resistance, testing and evaluation of the corrosion resistance. The influence of the antimony to the Al-Si alloys properties is described further in the introduction. The experimental part describes the experimental samples which were prepared for the experiment and further they were exposed to the loading in the atmospheric conditions for a period of the 3 months. The experimental samples were evaluated macroscopically and microscopically. The results of the experiment were documented and the conclusions in terms of the antimony impact to the corrosion resistance of the Al-Si alloy were concluded. There was compared the corrosion resistance of the Al-Si alloy antimony alloyed (with the different antimony content) with the results of the Al-Si alloy without the alloying after the corrosion load in the atmospheric conditions in the experiment.