Metallurgy and Foundry Engineering
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ISSN 1230-2325
e-ISSN: 2300-8377
Issue Date
2017
Volume
Vol. 43
Number
No. 3
Description
Journal Volume
Metallurgy and Foundry Engineering
Vol. 43 (2017)
Projects
Pages
Articles
Research on influence of modification on structure and mechanical properties of manganese-iron brass CuZn40Mn3Fe
(Wydawnictwa AGH, 2017) Romankiewicz, Remigiusz; Romankiewicz, Ferdynand
Research on the modification of manganese-iron brass CuZn40Mn3Fe with the use of variable additions of titanium and boron have shown that these additives cause fragmentation (refinement) of the structures (grains and precipitates of phase a) and an increase in the amount of precipitations of phase a in the brass structure. As a result of this modification, growth in the brass impact resistance (from 40 J/cm2 to 46-48 J/cm?) and tensile strength (from 400 MPa to 509 MPa) are achieved.
Design of new casting alloys of Al-Mg-Si-Mn system with alloying additions, its structure, and mechanical properties
(Wydawnictwa AGH, 2017) Bojko, Vìctorìâ; Czekaj, Edward; Warmuzek, Małgorzata; Mihalenkov, Kostântin Vìktoroviĉ
The strength of Al-Mg-Si-Mn casting alloy strongly depends on Mg content in solid solution and precipitation of strengthening phases. Alloys with the nominal composition AlMg5Si2Mn with addition of Li and Ti+Zr were studied by means of differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and energy dispersive X-Ray analysis (EDX). DSC measurements show that the eutectic melting temperature was about 595°C and it is higher than that of commercial A356 casting alloy. The macro- and microhardness tests show that in as-cast state hardness were higher than for A356 and continuously growth during artificial aging. TEM investigations reveal that during artificial aging three different precipitation types are forms in the alloy matrix. Two of them belong to the different structures of Mg?Si precipitates. Appearance of the third one identified as d'-Al?Li phase represent that Al-Mg-Si system can be successfully used for designing of Li-containing casting alloy which is not developed yet.
Comparison of impact of immersed and micro-jet cooling during quenching on microstructure and mechanical properties of hypoeutectic silumin AlSi7Mg0.3
(Wydawnictwa AGH, 2017) Czekaj, Edward; Kwak, Zofia; Garbacz-Klempka, Aldona
This article presents research the results of the mechanical properties at the ambient temperature of hypoeutectic cast silumin EN AC-AlSi7Mg0.3 (according to EN 1706:2011, analogic to alloy A356 according to AA - the Aluminum Association). As related to the commonly known and used process of immersion during quenching, the research also used a micro-jet system of cooling. After quenching, the experimental samples were also submitted to artificial aging in three different variations. The achieved results were compared with the mechanical properties of the alloy in the as-cast state. Samples from the experimental alloy were subjected to micro-jet cooling during quenching, in principle, they had a similar level of properties as related to the samples that were cooled by immersion, only in some cases did the micro-jet cooling give better results. Further works in the field should be aimed at constructing machines for micro-jet cooling with water pressure levels significantly higher than the typical pressure of community waterworks.
Evaluation of changes of stereological parameters of eutectic phases in AlSiMg alloy after precipitation hardening
(Wydawnictwa AGH, 2017) Grzegorek, Justyna; Olszowska-Sobieraj, Barbara; Tarasek, Anna; Lewicki, Piotr
Qualitative microstructure investigations of the AlSiMg alloy's microstructure in both its original state (with the characteristic primary structure) and after precipitation hardening revealed the significant heterogeneity of the eutectic phases concerning their shape, size, and distribution. An evaluation of the stereological parameters of the eutectic phases was carried out. The computer- -image analysis was performed in order to define the fraction of the relative volume and shape of the eutectic phases and to establish their influence on the mechanical properties.
Nucleation of microcracks and their propagation in gravity-cast Al-Si and Al-Li alloys
(Wydawnictwa AGH, 2017) Grzegorek, Justyna; Tarasek, Anna; Olszowska-Sobieraj, Barbara; Maj, Łukasz
This article discusses the nucleation and propagation of microcracks in gravity-cast aluminum- -silicon and aluminum-lit alloys. Microstructural observations were made on both an optical microscope and a scanning electron microscope. In addition, hardness measurements were made using the Vickers indenter and strength tests - a static compression test. Experiments have allowed us to determine the very important differences in both the nucleation and propagation of microcracks emerging after crossing the yield point between gravity-cast aluminum-silicon aluminum alloys.