Effects of Growth Rates and Compositions on Dendrite Arm Spacings in Directionally Solidified Al-Zn Alloys

Küçük Resim Yok

Tarih

2017

Dergi Başlığı

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Cilt Başlığı

Yayıncı

Springer Boston

Erişim Hakkı

info:eu-repo/semantics/closedAccess

Özet

Dendritic spacing can affect microsegregation profiles and also the formation of secondary phases within interdendritic regions, which influences the mechanical properties of cast structures. To understand dendritic spacings, it is important to understand the effects of growth rate and composition on primary dendrite arm spacing (?1) and secondary dendrite arm spacing (?2). In this study, aluminum alloys with concentrations of (1, 3, and 5 wt pct) Zn were directionally solidified upwards using a Bridgman-type directional solidification apparatus under a constant temperature gradient (10.3 K/mm), resulting in a wide range of growth rates (8.3–165.0 µm/s). Microstructural parameters, ?1 and ?2 were measured and expressed as functions of growth rate and composition using a linear regression analysis method. The values of ?1 and ?2 decreased with increasing growth rates. However, the values of ?1 increased with increasing concentration of Zn in the Al-Zn alloy, but the values of ?2 decreased systematically with an increased Zn concentration. In addition, a transition from a cellular to a dendritic structure was observed at a relatively low growth rate (16.5 µm/s) in this study of binary alloys. The experimental results were compared with predictive theoretical models as well as experimental works for dendritic spacing. © 2017, The Minerals, Metals & Materials Society and ASM International.

Açıklama

Anahtar Kelimeler

Kaynak

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

WoS Q Değeri

Q2

Scopus Q Değeri

Q1

Cilt

48

Sayı

12

Künye