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Morphology of intermetallic phases in Al-Si cast alloys and their fracture behaviour

Hurtalova L., Tillova E., Chalupova M., Belan J.

Production Engineering Archives

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2015

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Vol. 6, No. 1

2--5

EN

Applications of Al-Si cast alloys in recent years have increased especially in the automotive industry (dynamic exposed cast, engine parts, cylinder heads, pistons and so on). Controlling the microstructure of secondary aluminium cast alloys is very important, because these alloys contain more additional elements that form various intermetallic phases in the structure. Therefore, the contribution is dealing with the valuation type of intermetallic phases and their identification with using optical and scanning microscopy. Some of the intermetallic phases could be identified on the basis of morphology but some of them must be identified according EDX analysis. The properties of aluminium alloy are affected by morphology of intermetallic phases and therefore it is necessary to study morphology and its fracture behaviour. The present work shows morphology and typical fracture behaviour as the most common intermetallic phases forming in Al-Si alloys.

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Evaluation of Sb effect onto eutectic Si changes and mechanical properties in an 4xxx Al cast alloys series

Hurtalova L., Tillova E., Chalupova M., Farkasova M.

Production Engineering Archives

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2014

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Vol. 3, No. 2

2--5

EN

The purpose of this article is to examine the effect of modifier based on AlSb10 on the structure and mechanical properties of the AlSi7Mg0.3 and AlSi6Cu4 cast alloys. The changes of these parameters were studied on samples in untreated states (without heat treatment). Structural changes were studied on light and scanning electron microscopes. Several types of etching were used, which included normal black and white etching (0.5% HF), colour etching (Weck-Al) and deep etching (HCl), for studying structural parameters morphology. The influence of modifier on mechanical properties (UTS, Brinell hardness test) was studied at room temperature. The present work shows that the antimony has not had a significant effect on mechanical properties (UTS, Brinell hardness test), but structural parameters were changed.

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On the mechanical properties and structure of age-hardened AlSi9Cu3 cast alloy

Hurtalova L., Tillova E.

International Journal of Applied Mechanics and Engineering

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2010

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Vol. 15, no 2

355-362

EN

The paper describes the influence of age-hardening by solution treatment at 515 C with holding time 4 hours, water quenching at 40 C and artificial aging at different temperature 130 C, 150 C and 170 C with different holding time 2, 4, 8, 16 and 32 hours on mechanical properties (strength tensile and Brinell hardness) and changes in the morphology of eutectic Si, Fe-rich and Cu-rich intermetallic phases in secondary (recycled) AlSi9Cu3 cast alloy. The structure with of black-white etching was observed (Dix-Keller, H2SO4). A quantitative study of changes in the morphology of eutectic Si, Cu-rich and Fe-rich phases was carried out using Image Analyzer software NIS-Elements. The analysis of intermetallic phases was performed on SEM using EDX. Mechanical properties were measured in line with STN EN ISO. Age-hardening led to changes in the microstructure including spheroidization and coarsening of eutectic silicon, gradual disintegration, shortening and thinning of Fe-rich intermetallic phases, the dissolution of precipitates and the precipitation of finer hardening phase (Al2Cu), further increase in the hardness and tensile strength in the alloy.