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The Influence of Mg Additive on the Structure and Electrical Conductivity of Pure Copper Castings

Kranc M., Sikora G., Górny M., Garbacz-Klempka A.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 4

85--90

EN

The aim of this paper was to attain defect free, pure copper castings with the highest possible electrical conductivity. In this connection, the effect of magnesium additives on the structure, the degree of undercooling (ΔTα = Tα-Tmin, where Tα – the equilibrium solidification temperature, Tmin – the minimum temperature at the beginning of solidification), electrical conductivity, and the oxygen concentration of pure copper castings have been studied. The two magnesium doses have been investigated; namely 0.1 wt.% and 0.2 wt.%. A thermal analysis was performed (using a type-S thermocouple) to determine the cooling curves. The degree of undercooling and recalescence were determined from the cooling and solidification curves, whereas the macrostructure characteristics were conducted based on a metallographic examination. It has been shown that the reaction of Mg causes solidification to transform from exogenous to endogenous. Finally, the results of electrical conductivity have been shown as well as the oxygen concentration for the used Mg additives.

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Effect of Titanium and Boron on the Stability of Grain Refinement of Al-Cu Alloy

Górny M., Sikora G., Kawalec M.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 3

35--38

EN

The present research was conducted on thin-walled castings with 5 mm wall thicknesses. This study addresses the effect of the influence of different master alloys, namely: (1) Al-5%Ti-1%B, (2) Al-5%Ti and (3) Al-3%B, respectively on the structure and the degree of undercooling (ΔTα = Tα-Tmin, where Tα - the equilibrium solidification temperature, Tmin - the minimum temperature at the beginning of α(Al) solidification) of an Al-Cu alloy. The process of fading has been investigated at different times spent on the refinement treatment ie. from 3, 20, 45 and 90 minutes respectively, from the dissolution of master alloys. A thermal analysis was performed (using a type-S thermocouple) to determine cooling curves. The degree of undercooling and recalescence were determined from cooling and solidification curves, whereas macrostructure characteristics were conducted based on a metallographic examination. The fading effect of the refinement of the primary structure is accompanied by a significant change in the number (dimension) of primary grains, which is strongly correlated to solidification parameters, determined by thermal analysis. In addition to that, the analysis of grain refinement stability has been shown with relation to different grain refinements and initial titanium concentration in Al-Cu base alloy. Finally, it has been shown that the refinement process of the primary structure is unstable and requires strict metallurgical control.

3

Ilościowa ocena wielkości i kształtu ziaren pierwotnych w odlewanych precyzyjnie elementach z nadstopu kobaltu MAR-M509

Adamiec J., Szczotok A., Cwajna J.

Inżynieria Materiałowa

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2006

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Vol. 27, nr 3

108-111

PL

W artykule przedstawiono rezultaty prac badawczych nad makrostrukturą powierzchni roboczej (rys. 1, 3a, 4a) oraz makrostrukturą przekroju poprzecznego (rys. 2, 3b, 4b) żaroodpornego komponentu wykonanego ze stopu MAR-M509. Opisano kolejne etapy postępowania mającego na celu wyznaczenie parametrów charakteryzujących ziarno w przypadku obu rodzajów badanych powierzchni. Efektem tych działań jest opracowanie kompleksowej i powtarzalnej procedury oceny ilościowej ziaren pierwotnych badanego komponentu. Ponadto procedura ta może stać sie punktem wyjścia przy próbach stworzenia podobnych procedur w odniesieniu do innych materiałów i innych komponentów.

EN

The paper has presented results of researches on work surface macrostructure (Fig. 1, 3a, 4a) and transverse cross section macrostructure (Fig. 2, 3b, 4b) of a heat-resistant component made of MAR-M509 alloy. Consecutive stages of procedure being aimed at determination of parameters characterizing grain in the case of both kinds of the analyzed surfaces were described. An effect of these activities was elaboration of a complex and repeatable procedure of quantitative description of the analyzed component’s primary grains. Moreover, the procedure could become a point of reference for trials of creating similar procedures for other materials and components.