The effect of zinc on the microstructure and phase transformations of casting Al-Cu alloys

Manasijević, Ivana; Štrbac, Nada; Živković, Dragana; Balanović, Ljubiša; Minić, Duško; Manasijević, Dragan

doi:10.5937/tehnika1604553m

Cited by 2 publications

(1 citation statement)

References 5 publications

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“…Povećanjem brzine hlađenja, oslobađanje toplote se povećava, a početak procesa očvršćavanja počinje na nižoj temperaturu od ravnotežne tačke topljenja. Ovaj efekat dodatno smanjuje veličinu zrna u konačnoj strukturi i poboljšava čvrstoću uzoraka [9]. Mehanička svojstva legura aluminijuma u velikoj meri zavise od veličine zrna u očvrsloj strukturi.…”

Section: Slika 4 -Efekat Brzine Hlađenja Na Vrednosti Pothlađenja Vre...unclassified

The effect of the refractory material on the phase transformation parameteres during forming of the Al-8wt%Si-3wt%Cu structure

Mitrašinović¹,

Nešković²,

Labus³

et al. 2023

Tehnika

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Solidification of the aluminum alloys takes place in heat-resistant refractory materials made of either metal or oxides that are stable at high temperatures. The significantly different thermal conductivities between metals and heat-resistant oxides cause solidification with significantly different cooling rates. In this work, we formed a secondary Al-8wt%Si-3wt%Cu alloy in a stainless steel mould, a thin-walled stainless steel cup, and a thick-walled zirconium oxide cup. The course of the formation of the solidified structure was monitored by immersed thermocouples, which enabled the computer analysis of the cooling curves. The parameters on which the cooling rate had the most significant influence are the undercooling values of the formation of primary aluminum crystals, the time of the growth of primary aluminum crystals and the total solidification time from the formation of the first solid crystals to the formation of a fully solidified structure. The Al-8wt%Si-3wt%Cu aluminum alloy formed in metal mould has a smaller grain size and consequently higher tensile strength, lower macro-porosity and less rough surface than the alloy formed in refractory oxide coatings. The examined heat-resistant refractory material influenced the formation of three basic micro-constituents in the Al-8wt%Si-3wt%Cu alloy in different time intervals, which led to the formation of a different microstructure, where the decision on the choice of material for the heat-resistant refractory material depends on the profitability of the entire process, the required quality of the external surfaces and required minimum strength of the final product.

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Section: Slika 4 -Efekat Brzine Hlađenja Na Vrednosti Pothlađenja Vre...unclassified

The effect of the refractory material on the phase transformation parameteres during forming of the Al-8wt%Si-3wt%Cu structure

Mitrašinović¹,

Nešković²,

Labus³

et al. 2023

Tehnika

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Monitoring the amount of formed solid phase in aluminum alloy under free cooling conditions

Mitrašinović,

Nešković,

Ristić

et al. 2023

Tehnika

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One of the most effective ways for the future design, production, analysis and optimization of new processes, involving phase change of materials, is the development of highly sensitive quantitative methods based on the detection of temperature changes during the solidification process and the correlation of these changes with changes in the treated material. In this work, the secondary Al-8wt%Si3wt%Cu alloy was formed from the liquid state under free cooling conditions. Characteristic transformation temperatures were identified and a method for monitoring the amount of solid phase during the solidification process was formalized. From the recorded cooling curve, the values of the first derivative were determined and the corresponding reference curve was formed. The area between the first derivative of the cooling curve and the reference curve was used to assess the amount of solidified part of the material during the solidification process. The obtained results showed that the proposed method is effective in obtaining data of the fraction solid at every moment of the solidifcation process, as well as that it can be further used to detect the number of phases and microconstituents in the formed structure, as well as an experimental examination of the latent heat of solidification of new materials. The method of monitoring the amount of solid phase, formed under free cooling conditions, does not require specific preparation of samples or complex laboratory equipment, and accordingly, in practical application it effectively replaces standard methods for detecting thermophysical properties of materials, such as differential thermal analysis or differential scanning calorimetry.

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The effect of zinc on the microstructure and phase transformations of casting Al-Cu alloys

Cited by 2 publications

References 5 publications

The effect of the refractory material on the phase transformation parameteres during forming of the Al-8wt%Si-3wt%Cu structure

The effect of the refractory material on the phase transformation parameteres during forming of the Al-8wt%Si-3wt%Cu structure

Monitoring the amount of formed solid phase in aluminum alloy under free cooling conditions

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