Journal of Casting & Materials Engineering
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ISSN 2543-9901
Issue Date
2018
Volume
Vol. 2
Number
No. 2
Description
Journal Volume
Journal of Casting & Materials Engineering
Vol. 2 (2018)
Projects
Pages
Articles
Effect of solution treatment on age-hardening behavior of Al-12Si-1Mg-1Cu piston alloy with trace-Zr addition
(AGH University of Science and Technology Press, 2018) Kaiser, Mohammad Salim
The influence of a solution treatment with a trace zirconium addition on the precipitation behavior of a cast Al-12%Si-1%Mg-1%Cu piston alloy has been reported. The alloys were prepared by controlled melting and casting. The cast alloys were given an age-hardening treatment having a sequence of homogenization, T6 solutionizing, quenching, and aging. Both the cast and solutionized samples were naturally aged for 58 days, isochronally aged for 60 minutes at different temperatures (up to 350°C), and isothermally aged at various temperatures (up to 225°C) for different periods of time (ranging from 15 to 360 minutes). The hardness values of the differently processed alloys were measured to understand the aging behavior of the alloys. Electrical resistivity changes with aging time and temperature were measured to understand the precipitation behavior of the alloys. It is observed that significant hardening takes place in the aged alloys due to the formation of GP zones as well as the formation of metastable phases. The solutionizing treatment improves the hardness because some alloying elements are re-dissolved during solution treatment to produce a solute-rich solid solution. The trace-added Zr hinders the softening due to the precipitation of $Al_{3}Zr$, which is very stable against coarsening and the re-dissolution of precipitates. Electrical resistivity decreases due to stress relieving, the dissolution of the metastable phase, and precipitation coarsening. The resistivity of the solutionized alloys decreases more due to the higher concentration of elements in the solid solution. A microstructural study of the alloys reveals that the solution treatment improves the distribution of the silicon grains. It is also observed that the alloys attained an almost fully re-crystallized state after aging at 350°C for 90 minutes.
Measurement of molding sand elasticity
(AGH University of Science and Technology Press, 2018) Major-Gabryś, Katarzyna; Grabarczyk, Aleksandra; Dobosz, Stanisław Marian; Jakubski, Jarosław; Morek, Jan; Beňo, Jaroslav
The progressive mechanization and automation of industrial equipment is the driving force of progress, not only in the field of production but also in the measuring and control equipment. In mold production, the automation of processes such as forming molds and cores along with their assembly has led to increases in serial production, reductions in defects, and the shortening of molding times, among others. Thanks to automation in mold and core departments and the use of all sorts of manipulators, mold production in foundries has gained momentum. Unfortunately, in addition to the mentioned advantages, there are also new challenges as to the quality and properties of the molding and core sands used in highly automated foundries.This article presents recent research on molding sand elasticity. The topic was introduced as an attempt to answer the new needs of highly mechanized foundries. The article discusses a new method of measuring the resistance of molding materials to undergoing mechanical deformation (molding sand elasticity), with an additional analysis of the bending strengths of the tested samples. Precise measurements, test sample preparation, and interpretation of the received results are presented in the article.
Review on oxide formation and aluminum recovery mechanism during secondary smelting
(AGH University of Science and Technology Press, 2018) Osoba, Lawrence Opeyemi; Owolabi, Oluwasegun Biodun; Talabi, Segun Isaac; Adeosun, Samson Oluropo
The remelting, refining, and casting process of aluminum alloys often generate aluminum dross containing primarily oxides and nitrides of aluminum and entrapped metallic aluminum at the surface of the molten metal as a result of reactions with - in the furnace atmosphere at elevated temperatures. The handling of dross is an expensive but necessary activity during aluminum smelting. Furthermore, the amorphous $Al_{2}O_{3}$ oxide film formed on the pure molten aluminum surface due to the liquid metal randomly distributed atoms is impermeable to the diffusion of aluminum metal and oxygen. In amorphous materials, there is a low mobility of the charge carriers and an absence of preferred diffusion paths. This film can transform to crystalline $Al_{2}O_{3}$ by nucleation and grows with time and opportunity. This review discusses the mechanism of oxide formation and the aluminum metal recovery processes.