J 2015

The Use of Colour Metallography and EDS for Identification of Chemical Heterogeneity of Selected Aluminium Alloys Copper and Zinc Alloyed.

VIKTORIE, Weiss a Jaroslava SVOBODOVÁ

Základní údaje

Originální název

The Use of Colour Metallography and EDS for Identification of Chemical Heterogeneity of Selected Aluminium Alloys Copper and Zinc Alloyed.

Název česky

Využití barevné metalografie a EDS pro identifikaci chemické heterogenity u vybraných hliníkových slitin.

Autoři

VIKTORIE, Weiss (203 Česká republika, garant, domácí) a Jaroslava SVOBODOVÁ (203 Česká republika)

Vydání

Manufacturing Technology, Ústí nad Labem, Univerzita J. E. Purkyne, 2015, 1213-2489

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

20501 Materials engineering

Stát vydavatele

Česká republika

Utajení

není předmětem státního či obchodního tajemství

Kód RIV

RIV/75081431:_____/15:00000562

Organizační jednotka

Vysoká škola technická a ekonomická v Českých Budějovicích

Klíčová slova česky

krystalová segregace; barevna metalografie; homogenizační žíhaní; barevné leptání; AlCu4MgMn; AlZn5,5MgCu; EDS

Klíčová slova anglicky

crystal segregation; colour metallography; intermetallic phase; eutectic; colour etching; AlCu4MgMn; AlZn5.5MgCu; EDS

Štítky

Příznaky

Recenzováno
Změněno: 6. 4. 2016 08:06, Věra Kostková

Anotace

V originále

Aluminium alloys with higher content of alloying elements are very susceptible to the emergence of crystal segregation that significantly affects the mechanical, physical and chemical properties of these alloys. Crystal segregation is called chemical heterogeneity in microscale and is formed during crystallization. Crystallization of alloys does not occur at a particular temperature, as is the case of pure metals, but in a certain temperature interval. During cooling of the melt occurs to formation of different regions within the dendritic cell that differs in chemical composition. Generally is crystal segregation defined as chemical heterogeneity formed during alloy crystallization that is enriched or deprived of alloying elements and impurities that segregate unevenly across the surface of the dendrites. In the central area of the dendritic cells is alloy deprived of alloying elements, while the outer parts of dendritic cells and in space between dendrites is the concentration of alloying elements richer. This concentration has a hyperbolic course, when the central region of dendritic cells has the lowest concentration of the alloying elements and the outer part of dendrite boughs and interdendritic space have the maximum. Distribution of individual elements has a recurring character and can be described by sine function. The distance between two main axes of dendritic cells is affected by the temperature interval between the liquidus and solidus for the given alloy, the cooling rate of the melt and temperature gradient during solidification. Formation of the crystal segregation in aluminium alloys rich in alloying element and additives cannot be prevented, it is possible only influence its scope and with the right choice of heat treatment parameters can be suppressed. To suppress the crystal segregation the castings are subjected to heat treatment which is called homogenization annealing. It is the diffusion process in which there occurs to a balancing of chemical composition of alloy and the uniformity of its structure.