Variation of dendrite arm spacing in Al-rich Zn-Al off-eutectic alloys

Tunca, N.; Smith, Richard W.

doi:10.1007/bf01174041

Cited by 37 publications

(18 citation statements)

References 21 publications

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“…Solidification processing parameters (V, G, C 0 , and even diameter of the sample) affect the microstructures (k 1 , k 2 ). [21][22][23]39,40,[42][43][44][45][46][47][48][49][50][51] Throughout the experiment, all solidification processing parameters, except the growth rates, were kept constant.…”

Section: B the Effect Of Growth Rate On Dendritic Spacingsmentioning

confidence: 99%

Effect of Growth Rate on the Microstructure and Microhardness in a Directionally Solidified Al-Zn-Mg Alloy

Acer

Çadırlı

Erol

et al. 2016

Metall Mater Trans A

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The Al-5.5Zn-2.5Mg (wt pct) ternary alloy was prepared using a vacuum melting furnace and a casting furnace. Five samples were directionally solidified upwards at a constant temperature gradient (G = 5.5 K/mm) under different growth rates (V = 8.3-165 lm/s) in a Bridgman-type directional solidification furnace. The primary dendrite arm spacing, k 1 , secondary dendrite arm spacing, k 2 , and microhardness, HV, of the samples were measured. The effects of V on k 1 , k 2 and HV properties of the Al-Zn-Mg alloy were studied by microstructure analysis and mechanical characterization. Microstructure characterization of the alloys was carried out using optical microscopy, scanning electron microscopy, wavelength-dispersive X-ray fluorescence spectrometry, and energy dispersive X-ray spectroscopy. From the experimental results, it is found that the k 1 , k 2 values decrease, but HV values increase with the increase in V, and HV values decrease with the increase in k 1 and k 2 . Dependencies of dendritic spacing and microhardness on the growth rate were determined using linear regression analysis. The growth rate, microstructure, and Hall-Petch-type relationships obtained in this work have been compared with the results of previous studies.

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Section: B the Effect Of Growth Rate On Dendritic Spacingsmentioning

confidence: 99%

Effect of Growth Rate on the Microstructure and Microhardness in a Directionally Solidified Al-Zn-Mg Alloy

Acer

Çadırlı

Erol

et al. 2016

Metall Mater Trans A

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“…Em literatura, diversos autores reportam tanto a influência da taxa de resfriamento, concentração nominal de soluto, gradiente térmico na morfologia microestrutural [4][5][6][7][16][17][18][19][20][21][22][23][24]. A mesma tendência é mostrada por esses autores, ou seja, uma maior taxa associada a determinado teor de soluto e gradiente térmico imposto propiciam estrutura dendrítica ao passo que menores taxas resultam em células.…”

Section: Resultados E Discussõesunclassified

Efeitos da agitação mecânica e de adição de refinador de grão na microestrutura e propriedade mecânica de fundidos da liga Al-Sn

2009

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RESUMOO objetivo deste artigo foi avaliar os efeitos da agitação mecânica e de adição de refinador de grão na macro e microestrutura e propriedades mecânicas resultantes de três (03) diferentes procedimentos de fundição utilizando-se de uma liga Al-10%Sn. Os processos de fundição para obtenção das amostras foram: i)fundição por gravidade convencional, ii) fundição por gravidade com agitação mecânica do líquido em resfriamento, iii) fundição por gravidade com adição de refinadores de grão, particularmente adição de 1,5% (em peso) da liga-mãe Al-5%Ti-1%B e iv) fundição por gravidade com adição de refinador de grão e agitação mecânica. Resultados experimentais mostraram que os diferentes procedimentos de fundição propiciaram diferentes valores médios dos tamanhos dos grãos correlacionados com diferentes taxas de resfriamento. Taxas na ordem de 0,60 a 0,75 o C/s propiciaram microestruturas celulares e taxas na ordem de 1,75 a 2,55 o C/s resultaram em morfologias dendríticas. Foram avaliados também os níveis de porosidade entre as amostras estudadas. Foram correlacionados os resultados do comportamento mecânico, particularmente, limite de resistência à tração, limite de escoamento e alongamento específico com os tamanhos dos grãos, os espaçamentos dendríticos e celulares e os níveis de porosidade resultantes dos três diferentes procedimentos de obtenção das amostras. Conclui-se que o controle da microestrutura do lingote pode ser usado como um método alternativo para produzir componentes fundidos com melhores resultados de propriedades mecânicas e qualidade dos fundidos.Palavras-chaves: agitação mecânica, refinador de grão, porosidade, liga Al-Sn, propriedade mecânica. Effects of mechanical agitation and of the addition of grain refiner on the microstructure and mechanical properties of castings of the Al-Sn alloy. ABSTRACTThe aim of this article was to evaluate the effects of mechanical stirring and grain refiner addition in three different Al-10wt%Sn casting alloys on their resulting macro and microstructures and mechanical properties. These samples were obtained by using: i) die casting, ii) casting with mechanical stirring, iii) die casting using grain refiner (master alloy Al-5wt%Ti-1wt%B) and iv) die casting with grain refiner and mechanical stirring. Experimental results presented different mean grain sizes and different cooling rates when different casting procedures were applied. Cellular and dendritic morphologies were observed when ranges of cooling rates of about 0.6 to 0.75 o C/s and of 1.75 to 2.55 o C/s were employed, respectively. Porosity levels of all studied alloy samples were also analyzed. Results of the mechanical behavior, particularly, ultimate tensile strength, yield strength and specific elongation were correlated with mean grain sizes, dendritic arm and cellular spacings and porosity levels attained for the three different cast Al-10wt%Sn alloy samples. The control of the resulting microstructure of the as-cast product may be used as an alternative way to produce sound casting alloy compone...

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“…[14,15] It has been found that the primary dendrite arm spacing becomes larger when solidifying upward due to solute accumulation between dendrites. [16][17][18] Drainage or enrichment of rejected solute during growth depends on the direction of growth. [17] Also, this depends on the density of rejected solute; [18] e.g., drainage occurs during downward solidification for the case of alloys with high density solute elements.…”

Section: Introductionmentioning

confidence: 99%

In-Situ Analysis of Coarsening during Directional Solidification Experiments in High-Solute Aluminum Alloys

Ruvalcaba

Mathiesen

Eskin

et al. 2008

Metall Mater Trans B

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Coarsening within the mushy zone during continuous directional solidification experiments was studied on an Al-30 wt pct Cu alloy. High brilliance synchrotron X-radiation microscopy allowed images to be taken in-situ during solidification. Transient conditions were present during directional solidification. Under these conditions, solute-rich settling liquid flow affects the dendritic array and thus coarsening. Coarsening was studied by following the secondary dendrite arm spacing (SDAS) of a developing dendrite at different local solidification times according to the mush depth and instant interface velocity. Solute enrichment and liquid flow cause deceleration and acceleration of the solidification front, which in turn influences both the mush depth and local growth and coarsening due to variations in solutal gradients and thus local undercooling. In addition, spacing between neighboring dendrites (i.e., primary dendrite arm spacing), which determines permeability within the mushy zone, affects the development of high-order branches.

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Variation of dendrite arm spacing in Al-rich Zn-Al off-eutectic alloys

Cited by 37 publications

References 21 publications

Effect of Growth Rate on the Microstructure and Microhardness in a Directionally Solidified Al-Zn-Mg Alloy

Effect of Growth Rate on the Microstructure and Microhardness in a Directionally Solidified Al-Zn-Mg Alloy

Efeitos da agitação mecânica e de adição de refinador de grão na microestrutura e propriedade mecânica de fundidos da liga Al-Sn

In-Situ Analysis of Coarsening during Directional Solidification Experiments in High-Solute Aluminum Alloys

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