Directional solidification of aluminium–copper alloys

Gündüz, Mehmet; Çadırlı, Emin

doi:10.1016/s0921-5093(01)01649-5

Cited by 333 publications

(153 citation statements)

References 88 publications

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“…To measure the dendrite arm spacings in several samples from the metal/mold interface to region columnar zone the samples were analyzed in an optical microscope Neophot -32, using the method described by Gündüz and Çadirli (2002). The measurements were performed using the software Q500 MC Leika of Cambridge Ltda, interconnected under a microscope.…”

Section: Methodsmentioning

confidence: 99%

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A Comparative study of solidification of Al-Cu alloy under flow of cylindrical radial heat and the unidirectional vertically

et al. 2014

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ABSTRACT. In spite of technological importance of solidification of metallic alloys under radial heat flow, relatively few studies have been carried out in this area. In this work the solidification of Al 4.5 wt% Cu cylinders against a steel massive mold is analyzed and compared with unidirectional solidification against a cooled mold. Initially temperature variations at different positions in the casting and in the mold were measured during solidification using a data acquisition system. These temperature variations were introduced in a numerical method in order to determine the variation of heat transfer coefficient at metal/mold interface by inverse method. The primary and secondary dendrite arm spacing variations were measured through optical microscopy. Comparisons carried out between experimental and numerical data showed that the numerical method describes well the solidification processes under radial heat flux.Keywords: unidirectional solidification, radial heat flow, heat transfer coefficient, aluminum alloy.Estudo comparativo da solidificação da liga Al-Cu sob fluxo de calor radial cilíndrico e unidirecional ascendente RESUMO. A despeito da importância tecnológica da solidificação de ligas metálicas sob fluxo de calor radial, relativamente poucos estudos estão sendo realizados nessa área. Neste trabalho, a solidificação da liga Al-4,5%Cu em molde de aço radial cilíndrico é analisada e comparada com a solidificação unidirecional em molde resfriado. Inicialmente, a variação de temperatura em diferentes posições no metal e no molde foram medidas durante a solidificação usando um sistema de aquisição de dados. Essas variações de temperatura foram introduzidas num método numérico para determinar a variação do coeficiente de transferência de calor na interface metal/molde pelo método inverso. Os espaçamentos interdendríticos são determinados a partir das micrografias. Comparações entre variações e temperaturas calculadas numéricas e experimentalmente comprovaram que o método numérico descreve satisfatoriamente o processo de solidificação.Palavras-chave: solidificação unidirecional, fluxo de calor radial, coeficiente de transferência de calor, ligas alumínio.

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Section: Methodsmentioning

confidence: 99%

“…Several other researchers via the solidification metals, studied the microstructures resulting from unidirectional solidification radial and under the most diverse geometries, temperature conditions and chemical compositions (GÜNDÜZ;ÇARDILI, 2002;SANTOS et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

A Comparative study of solidification of Al-Cu alloy under flow of cylindrical radial heat and the unidirectional vertically

et al. 2014

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“…The positions of the thermocouples were measured by electronic calipers having an accuracy of ±0.02 mm after quench. Careful experimental measurements showed that the pulling rates of the samples were equal to the value of the growth velocities 30 . The solidification time and solidified distance were also measured for the run and their ratio gives the growth velocity.…”

Section: Measurement Of Solidification Processing Parameters (G and V)mentioning

confidence: 99%

“…The primary dendrite arm spacing, PDAS (λ 1 ), was measured on the longitudinal and transverse sections of each sample by using the linear intercept method [30][31][32] . In the linear intercept method, λ 1L is obtained on the longitudinal section by measuring the distance between adjacent dendrite tips.…”

Section: Measurement Of Primary and Secondary Dendrite Arm Spacingmentioning

confidence: 99%

Microstructural Evolution and Mechanical Properties in Directionally Solidified Sn–10.2 Sb Peritectic Alloy at a Constant Temperature Gradient

et al. 2016

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The Sn-10.2 Sb (mass fraction) peritectic alloy was prepared using a vacuum melting furnace and a hot filling furnace. The samples were directionally solidified upwards at steady state conditions with a constant temperature gradient (G=4.5±0.2 K. mm -1 ) under different growth velocities (V=13.3-266.7 µm. s -1 ) in a Bridgman-type directional solidification apparatus. The effects of the growth velocity (V) on the dendritic spacings were investigated. Primary dendrite arm spacing (PDAS) of α phase in directionally solidified Sn-10.2 Sb peritectic alloy was measured on the longitudinal and transverse sections of 4 mm diameter cylindrical samples. Secondary dendrite arm spacing (SDAS) was measured on the longitudinal section. The experimental results show that the measured PDAS (λ 1L , λ 1T ) and SDAS (λ 2 ) decrease with increasing growth velocity. The dependence of PDAS, SDAS, microhardness (HV) and compressive strength (σ c ) on the growth velocity were determined by using a linear regression analysis. The experimental results were compared with the previous experimental results and the results of the experimental models.

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“…Este arranjo experimental é importante exatamente por este motivo, ou seja, promove o contraponto com a solidificação nos sistemas verticais permitindo a verificação da influência de correntes convectivas sobre a microestrutura de solidificação obtida, mostrando as diferenças entre as três configurações quando são solidificadas ligas de mesma composição. Na literatura, observa-se que a grande maioria dos estudos desenvolvidos dedica-se a investigar a formação de estruturas dendríticas obtidas durante a solidificação unidirecional de materiais metálicos somente nos sistemas verticais considerando o regime estacionário de extração de calor [2][3][4][5][6]. Assim, poucos são os trabalhos que tratam da solidificação unidirecional em sistemas com configuração horizontal em regime transiente [7][8][9] uma vez que esta é mais complexa sob o ponto de vista da determinação das variáveis térmicas de solidificação.…”

Section: Introductionunclassified

Espaçamentos dendríticos primários da liga Sn-5%Pb solidificada direcionalmente em um sistema horizontal

et al. 2012

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RESUMOEste trabalho desenvolve um estudo teórico-experimental sobre a correlação entre parâmetros térmicos e os espaçamentos dendríticos primários da liga Sn-5%Pb solidificada direcionalmente em um sistema horizontal sob condições transientes de extração de calor. Os perfis de temperatura foram medidos em diferentes posições do lingote e os dados obtidos foram armazenados automaticamente. São apresentados resultados para o coeficiente de transferência de calor na interface metal/molde o qual foi calculado a partir de uma análise comparativa entre os perfis térmicos experimentais e valores teóricos fornecidos por um modelo numérico. Um método teórico-experimental é aplicado para determinar as velocidades de deslocamento da isoterma liquidus e as taxas de resfriamento. Os resultados teóricos e experimentais levantados apresentaram boa concordância. Um estudo comparativo é realizado entre os dados encontrados neste trabalho e aqueles apresentados na literatura para os espaçamentos dendríticos primários da liga investigada quando solidificada direcionalmente nos sistemas verticais ascendente e descendente, sob as mesmas condições assumidas neste trabalho. A análise das microestruturas indica que os espaçamentos dendríticos primários são bastante influenciados pelos parâmetros térmicos de solidificação.Palavras-chave: solidificação horizontal, espaçamento dendrítico primário, ligas Sn-Pb. ABSTRACTIn order to investigate the effect of thermal parameters on the primary dendritic spacings of Sn-5%Pb alloy, horizontal directional solidification experiments have been carried out under unsteady state heat flow conditions. Thermocouples have been connected with the metal, and the time-temperature data have been recorded automatically. The results include metal/mold heat transfer coefficient determined from comparisons between the experimental thermal profiles and simulations provided by a numerical model. A combined theoretical and experimental approach is developed to determine the solidification thermal parameters: tip growth rates, and cooling rates. The experimental and calculated values have shown a good agreement. A comparative study between experimental data of this work and those from the literature proposed to predict the primary spacings during upward and downward vertical unsteady-state directional solidification of Sn-Pb alloys is presented. The observation of the microstructures has indicated that the primary dendritic spacings have been affected by the direction of growth, increasing in conditions of horizontal solidification when compared with those obtained during vertical solidification.

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Directional solidification of aluminium–copper alloys

Cited by 333 publications

References 88 publications

A Comparative study of solidification of Al-Cu alloy under flow of cylindrical radial heat and the unidirectional vertically

A Comparative study of solidification of Al-Cu alloy under flow of cylindrical radial heat and the unidirectional vertically

Microstructural Evolution and Mechanical Properties in Directionally Solidified Sn–10.2 Sb Peritectic Alloy at a Constant Temperature Gradient

Espaçamentos dendríticos primários da liga Sn-5%Pb solidificada direcionalmente em um sistema horizontal

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