Thermal parameters and microstructure during transient directional solidification of a monotectic Al–Bi alloy

Silva, Adrina P.; Spinelli, José Eduardo; Garcia, Amauri

doi:10.1016/j.jallcom.2008.07.021

Cited by 43 publications

(31 citation statements)

References 18 publications

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“…The experiments which were performed with the Al-3.2 wt% Bi monotectic alloy had the initial melt temperature (Tp) adjusted at about 5% above the monotectic temperature (TM) while the experiment performed with the Al-2.0 wt% Bi was started with 5% above the liquidus temperature (TL). The enlarged partial phase diagram of the Al-Bi system, has been shown in a previous study [13] and permits a clear visualization of phases and transformation temperatures in the hypomonotectic range of Al-Bi alloys. 1 ThermoCalc software is an exclusive copyright property of the STT Foundation (Foundation of Computational Thermodynamics, Stockholm, Sweden).…”

Section: Methodsmentioning

confidence: 75%

“…It is also highlighted that published values of C for Al-Bi monotectic differ up to one order of magnitude (between 10 −14 and 10 −15 ). In a recent study, Silva et al [13] have found a C-value of 1.7 × 10 −12 concerning non-steady solidification conditions, which is about two orders of magnitude higher than those reported for the steady-state regime at any given growth rate. However, Carlberg and Bergman [9] reported that the the growth law for some irregular eutectics but also very similar to expressions for dendritic growth.…”

Section: Introductionmentioning

confidence: 73%

“…The experimental setups used in the upward and downward transient directional solidification experiments have been detailed in previous articles [13,22]. Heat is directionally extracted only through the water-cooled system, which permits a wide range of solidification thermal parameters to be analyzed.…”

Section: Methodsmentioning

confidence: 99%

“…Although several works cover the analysis of monotectic or offmonotectic compositions in the Al-Bi system [4,[6][7][8]10,11,13,16], little attention has been given to the microstructure evolution of hypomonotectic alloys. Most of the aforementioned studies have used Bridgman-type resistance heated furnaces to produce the directionally solidified monotectic samples.…”

Section: Introductionmentioning

confidence: 99%

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Microstructural evolution during upward and downward transient directional solidification of hypomonotectic and monotectic Al–Bi alloys

Silva

Spinelli

Garcia

2009

Journal of Alloys and Compounds

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Section: Methodsmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 73%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Microstructural evolution during upward and downward transient directional solidification of hypomonotectic and monotectic Al–Bi alloys

Silva

Spinelli

Garcia

2009

Journal of Alloys and Compounds

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“…As distintas morfologias dos sistemas monotéticos têm sido alvo de intensos estudos CALBERG;BERGMAN, 1985;DERBY;FAVIER, 1983;LOGRASSO;HELLAWELL, 1984;HELLAWELL, 1981;KAMIO et al, 1984;KAUKLER;ROSEMBERGER;CURRERI, 1997;OZAWA;MOTEGI, 2004;RATKE, 2005;RATKE;MULLER, 2005;GARCIA, 2009a, 2009b, SILVA et al, 2010YANG;LIU, 2001) durante as últimas décadas. Um dos parâmetros microestruturais normalmente investigados é o espaçamento interfásico, λ, sendo bastante comum a utilização da clássica relação para crescimento de sistemas eutéticos de Hunt e Jackson (GARCIA, 2007;STOCKER;RATKE, 1999): λ 2 v = C para representá-lo, ou ainda a relação de crescimento dendrítico proposta por Calberg e Bergman (1985), .…”

Section: Introductionunclassified

Lei de Crescimento em Função da Posição para Ligas do Sistema Monotético

Braga

Silva

Spinelli³

et al. 2016

Semina: Tech. Ex.

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ResumoLigas monotéticas apresentam aplicações promissoras em componentes automotivos resistentes ao desgaste. Muitos estudos têm sido realizados a fim de melhor compreender a reação monotética. Algumas pesquisas assumem que a evolução do espaçamento interfásico (λ) nas ligas monotéticas obedece à clássica relação utilizada para eutéticos: . . v G C λ = , ou ainda a relação de crescimento dendrítico , em que v é a velocidade de solidificação e C uma constante para ambos os casos, G é o gradiente de temperatura e a e b são constantes, entretanto, para alguns casos, as leis apresentadas não se mostraram válidas. No presente trabalho foram analisados os resultados desses experimentos de solidificação unidirecional em regime não estacionário, com as ligas hipomonotéticas Al-0,9%Pb e Al-5,5%In, com a liga monotética Al-1,2%Pb e com as ligas hipermonotéticas Al-5,0%Bi, Al-7,0%Bi e Al-2,1%Pb em configurações de extração de calor ascendente e descendente, a fim de propor nova lei de crescimento unicamente para sistemas monotéticos. Pôde-se estabelecer uma lei para crescimento de monotéticos em função da posição a partir da interface metal/molde, λ = k. (P) Monotectic alloys show promising applications in wear-resistant automotive components. Much research has been devoted in order to better comprehend monotectic reactions. Some researches assume that the interphase spacing evolution in monotectic alloys follows the classical relationship used for eutectics: λ2v = C, or the dendritic growth relationship , where v is the solidification velocity and C a constant value for both cases, G is the thermal gradient and a and b are constants. However, some studies reported that the aforementioned growth laws seem not to be valid for some cases. In the present study, the results of directional unsteady-state solidification experiments with hypomonotectic Al-0.9wt%Pb and Al-5.5wt%In, monotectic Al-1.2wt%Pb and hypermonotectic Al-5.0wt%Bi, Al-7.0wt%Bi and Al-2.1wt%Pb alloys, under different heat extracting configurations ( upward and downward) were taken into account to propose a new and exclusive growth law for monotectic systems. It was possible to establish a single monotectic growth law as a function of position from the metal/mold interface, λ = k.(P) 0,5.

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On the growth of the minority phase during downward transient directional solidification of hypomonotectic and monotectic Al–Pb alloys

et al. 2012

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Al-Pb alloys were solidified under non steady heat flow conditions using a casting assembly in order to promote vertical downward directional solidification. The downward configuration enables the effects of gravitydriven convection on the final microstructure to be evaluated since the collective movement of Pb-rich particles downwards is favored, due to density differences between the two coexisting liquid phases. Investigations have been made of the obtained solidification structures. Growth rates (v) and cooling rates (T Á ) of the Al-Pb alloys solidified downwards were experimentally determined by the cooling curves recorded along the casting length. The monotectic structure was characterized by metallography and a microstructural transition has been observed in all cases. The microstructure was characterized by well-distributed Pb-rich droplets in the aluminum-rich matrix from the casting cooled surface up to a certain position in the casting, followed by a mixture of fibers and strings of pearls from this point to the bottom of the casting. The increase in alloy lead content delays the formation of fibers for alloys solidified downwards, which occurs for v \ 0.48 mm/s and v \ 0.15 mm/s for Al-0.9 wt%Pb and Al-1.2 wt%Pb alloys, respectively. Experimental power laws relating the interphase spacing, k, to v and characterized by -2.0 and -6.5 exponents, were found to represent the growth of droplets and fibers, respectively, for both alloys solidified downwards.

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Thermal parameters and microstructure during transient directional solidification of a monotectic Al–Bi alloy

Cited by 43 publications

References 18 publications

Microstructural evolution during upward and downward transient directional solidification of hypomonotectic and monotectic Al–Bi alloys

Microstructural evolution during upward and downward transient directional solidification of hypomonotectic and monotectic Al–Bi alloys

Lei de Crescimento em Função da Posição para Ligas do Sistema Monotético

On the growth of the minority phase during downward transient directional solidification of hypomonotectic and monotectic Al–Pb alloys

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