The correlation between dendritic microstructure and mechanical properties of directionally solidified hypoeutectic Al-Ni alloys

Canté, Manuel V.; Spinelli, José Eduardo; Cheung, Noé; Garcia, Amauri

doi:10.1007/s12540-010-0039-2

Cited by 70 publications

(18 citation statements)

References 32 publications

(45 reference statements)

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“…13, the present experimental results are compared with the theoretical predictions furnished by the main predictive models existing in the literature, the Bouchard-Kirkaldy (BK) [35] and Hunt-Lu (HL) [36] models, concerning the growth of primary spacings in transient conditions. These models have been validated for the majority of binary alloys solidified upward directionally [6,9,11,23,[25][26][27][28][29][30][31][32][37][38][39][40][41][42][43][44]. It is possible to observe a good approximation between the experimental results of this work with the theoretical values of the BK model as well as the maximum theoretical values of the HL model.…”

Section: Resultsmentioning

confidence: 53%

Measurements of microhardness during transient horizontal directional solidification of Al-Rich Al-Cu alloys: Effect of thermal parameters, primary dendrite arm spacing and Al2Cu intermetallic phase

et al. 2015

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In this work, the effect of the growth rate (V L ) and cooling rate (T R ), primary dendritic arm spacing ( 1 ) and Al 2 Cu intermetallic phase on the microhardness was investigated during transient horizontal directional solidification of Al-3wt%Cu and Al-8wt%Cu alloys. Microstructural characterization of the investigated alloys was performed using traditional techniques of metallography, optical and SEM microscopy and X-Ray diffraction. The microhardness evolution as a function of the thermal and microstructural parameters (V L , T R , and  1 ) was evaluated using power and Hall-Petch type experimental laws, which were compared with other laws in the literature. In order to examine the effect of the Al 2 Cu intermetallic phase, microhardness measurements were performed in interdendritic regions. Finally, a comparative analysis was performed between the experimental data of this work and theoretical models from the literature that have been proposed to predict primary dendrite arm spacing, which have been tested in numerous works considering upward directional solidification.

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Section: Resultsmentioning

confidence: 53%

Measurements of microhardness during transient horizontal directional solidification of Al-Rich Al-Cu alloys: Effect of thermal parameters, primary dendrite arm spacing and Al2Cu intermetallic phase

et al. 2015

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“…Then, the temperature was reduced to 700 • C and held for 30 min before the directional solidification procedure. A detailed description of processing by transient directional solidification is given elsewhere [24,25]. Iron (Fe) was found to be the main impurity in the tested samples, which remained inside the suitable commercial Fe wt % spectrum of 0.205 ± 0.065.…”

Section: Experiments To Follow Solidification Kineticsmentioning

confidence: 99%

Tailoring of Microstructures and Tensile Properties in the Solidification of Al-11Si(-xCu) Brazing Alloys

Donadoni

Gomes

Garcia

et al. 2018

Metals

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Ternary Al-11wt %Si-(xwt %)Cu alloys are highly recommended as commercial filler metals for aluminum brazing alloys. However, very little is known about the functional inter-relations controlling the solidified microstructures characterizing processes such as torch and furnace brazing. As such, we evaluated two commercial brazing alloys, which are the Al-11wt %Si-3.0wt %Cu and Al-11wt %Si-4.5wt %Cu alloys: Cu contents typically trend in between the suitable alloying spectrum. We analyzed the effects of solidification kinetics over features such as the dendrite arm spacing and the spacing between particles constituting the eutectic mixture. Also, tensile properties were determined as a function of the dendrite microstructure dimensions. The parameters concerned for translating the solidification kinetics were either the cooling rate, or growth velocity related to the displacement of the dendrite tip, or the eutectic front. The relevant scaling laws representing the growth of these brazing alloys are outlined. The experimental results demonstrated that a 50% increase in Cu alloying (from 3.0 to 4.5 wt %) could be operated in order to obtain significant variations in the dendritic length-scale of the microstructure across the produced parts. Overall, the microstructures were constituted by an α-Al dendritic matrix surrounded by a ternary eutectic consisting of α-Al + Al 2 Cu + Si. The scale measurements committed to the Al 2 Cu eutectic phase pointed out that the increase in Cu alloying has a critical role on refining the ternary eutectic. the solidification process is essential, since its influence can be noted even in the finished product [3,6]. According to Zeren et al. [7] more research efforts are necessary for a better understanding of the mechanisms responsible for strength variations in Al-Si-xCu alloys.The solidification process and the intrinsic characteristics of the alloy to be solidified have a direct influence on the microstructure formation, which determines the final properties of a casting. The obtained casting parts exhibit mechanical characteristics that depend on inherent aspects occurring during solidification, such as: grain size, the scale of the phases forming the microstructure such as dendrite arm spacings and interphase spacings, the size and distribution of such phases, chemical composition heterogeneities, inclusions, and porosity. The understanding of solidification of aluminum alloys has fundamental importance for planning of manufacturing processes, since it allows a better understanding of the factors affecting microstructure, and consequently, the product quality [8][9][10][11][12][13].For the manufacturing of castings with predefined local properties, a widely used process is foundry technology (metal/mold casting processes). The cooling rate related to the process of heat transfer from the casting into the mold is an aspect acting in parallel, which conditions the change of the size and distribution of individual components within the resulting microstructure. The kind of crystall...

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“…O lingote da liga hipoeutética Bi-1,5%Ag (composição nominal) foi obtido através da utilização do dispositivo de solidificação unidirecional vertical ascendente, cujo detalhamento do aparato experimental pode ser encontrado na literatura [11]. O diagrama de fases do sistema Bi-Ag pode ser considerado como do tipo eutético simples (veja Figura 1 a seguir), com longo patamar de formação de estrutura eutética e ponto de reação eutética para o teor de 97,4%Bi e temperatura 262,5°C.…”

Section: Procedimento Experimentalunclassified

CORRELAÇÃO ENTRE MICROESTRUTURA E DUREZA DA LIGA LIVRE DE CHUMBO Bi-1,5%Ag

Macedo¹,

Silva²,

Spinelli³

2014

ABM Proceedings

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ResumoO estudo de ligas livres de Pb envolvendo o emprego de junções metálicas sob altas temperaturas tem recebido atenção especial, sendo desenvolvidas novas ligas com qualidade e desempenho adequados. Ligas Bi-Ag consistem em alternativas promissoras para a substituição das ligas de solda contendo Pb para tais aplicações, por isso devem ser melhor caracterizadas sob o aspecto de estruturas brutas de fusão. Assim, o presente trabalho objetiva investigar a liga hipoeutética Bi-1,5%Ag (%em peso) solidificada unidirecionalmente sob regime transitório de fluxo de calor. Será analisada a influência dos parâmetros térmicos de solidificação como velocidade de solidificação (VL), taxa de resfriamento (Ṫ) gradiente de temperatura (G) na microestrutura e na evolução de dureza da liga citada. Para determinação do perfil de dureza, foram realizados ensaios de dureza Vickers. Para obtenção e caracterização das microestruturas presentes no fundido Bi-1,5%Ag, fez-se o uso da microscopia ótica e da fluorescência de raios-x. Uma estrutura de dendritas facetadas de Bi circundadas pelo eutético Bi-Ag prevaleceu ao longo do lingote Bi-1,5%Ag. Verificou-se um aumento gradativo dos espaçamentos dendríticos primário (1) e secundário (2) à medida que a distância da base refrigerada foi aumentada. Em geral, os valores de dureza diminuíram para maiores valores de 1 e 2. Palavras-chave: Ligas Bi-Ag; Microestrutura; Solidificação; Dureza. AbstractThe study of Pb-free alloys involving the use of metallic connections under high temperatures has received special attention in the last few years, being developed new alloys with adequate quality and performance. Bi-Ag alloys appear as potential candidates to replace solder alloys containing Pb. Hence, such alloys are needed to be better characterized considering their as-cast or assoldered microstructures. The aim of this study is to investigate a lead-free Bi-1.5wt%Ag solder alloy solidified unsteady-state upward unidirectional conditions. The influence of thermal parameters as tip growth rate (VL), cooling rate (Ṫ) and thermal gradient (G) on the final microstructure and hardness properties will be examined. A hardness Vickers tester was used in order to determine the hardness profile of the Bi-1.5wt%Ag alloy. The directionally solidified microstructure was characterized by both light microscopy and fluorescence spectrometer. It was found that the as-cast structure was arranged by faceted Bi-rich dendrites sorrounded by a eutectic mixture (Bi+Ag). In general, the hardness values decrease for higher of 1 and 2 values.

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The correlation between dendritic microstructure and mechanical properties of directionally solidified hypoeutectic Al-Ni alloys

Cited by 70 publications

References 32 publications

Measurements of microhardness during transient horizontal directional solidification of Al-Rich Al-Cu alloys: Effect of thermal parameters, primary dendrite arm spacing and Al2Cu intermetallic phase

Measurements of microhardness during transient horizontal directional solidification of Al-Rich Al-Cu alloys: Effect of thermal parameters, primary dendrite arm spacing and Al2Cu intermetallic phase

Tailoring of Microstructures and Tensile Properties in the Solidification of Al-11Si(-xCu) Brazing Alloys

CORRELAÇÃO ENTRE MICROESTRUTURA E DUREZA DA LIGA LIVRE DE CHUMBO Bi-1,5%Ag

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