The columnar to equiaxed transition during the horizontal directional solidification of Sn–Pb alloys

Silva, José N.; Moutinho, Daniel J.; Moreira, Antonio Luciano Seabra; Ferreira, Itamar; Rocha, Otávio Fernandes Lima da

doi:10.1016/j.jallcom.2008.11.026

Cited by 25 publications

(30 citation statements)

References 29 publications

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“…In order to determine more accurate values of these parameters, the results of experimental thermal analysis, shown in Figure 4a have been used to generate a plot of position from the metal/ mold interface as a function of time corresponding to the liquidus front passing by each thermocouple. This methodology has been detailed in our recently published articles [7][8][9][10][11][12][13][14]. A curve fitting technique on such experimental points has generated a power function of position as a function of time (see Figure 4b).…”

Section: Resultsmentioning

confidence: 99%

“…The derivative of this function with respect to time has yielded values for VL, shown in Figure 5a. Figure 5b shows the TR profile, which was calculated by considering the thermal data recorded immediately after the passing of the liquidus front by each thermocouple [7][8][9][10][11][12][13][14]. It can be seen in Figures 5a and 5b that the use of a water cooled mold imposes higher values of VL and TR near the metal/mold interface and a decreasing profile along the casting due to the increasing thermal resistance of the solidified layer with distance from the heat-extracting surface.…”

Section: Resultsmentioning

confidence: 99%

“…Nowadays these alloys are supplied in a wide range of chemical compositions [1][2][3][4][5][6][7][8][9][10][11][12]. We highlight the Al-Cu-Si ternary system because of particular outstanding properties such as high mechanical strength, low weight and very good fluidity [3][4][5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…This is known that the values of 1, 2 and 3 are strongly influenced by solidification thermal parameters such as growth rate (VL) and cooling rate (TR) [1,2,3,[7][8][9][10][11][12]. Several directional solidification studies have been reported in the literature to characterize and quantify these parameters as a function of solute concentration C0, VL and TR.…”

Section: Introductionmentioning

confidence: 99%

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Influence of upward and horizontal growth direction on microstructure and microhardness of an unsteady-state directionally solidified Al-Cu-Si alloy

et al. 2016

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In order to analyze the effect of the growth direction on dendrite arm spacing (1) and microhardness (HV) during horizontal directional solidification (HDS), experiments were carried out with the Al-3wt.%Cu-5.5wt.%Si alloy and the results compared with others from the literature elaborated for upward directional solidification (UDS). For this purpose, a water-cooled directional solidification experimental device was developed, and the alloy investigated was solidified under unsteady-state heat flow conditions. Thermal parameters such as growth rate (VL) and cooling rate (TR) were determined experimentally and correlations among VL, TR, 1 and HV has been performed. It is observed that experimental power laws characterize 1 with a function of VL and TR given by: 1=constant(VL) -1.1 and 1=constant(TR) -0.55 . The horizontal solidification direction has not affected the power growth law of 1 found for the upward solidification. However, higher values of 1 have been observed when the solidification is developed in the horizontal direction. The interrelation of HV as function of VL, TR and 1 has been represented by power and Hall-Petch laws. A comparison with the Al-3wt.%Cu alloy from literature was also performed and the results show the Si element affecting significativaly the HV values.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of upward and horizontal growth direction on microstructure and microhardness of an unsteady-state directionally solidified Al-Cu-Si alloy

et al. 2016

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“…A metodologia experimental conduzida neste trabalho consistiu basicamente no projeto, construção e aferição de um dispositivo de solidificação direcional horizontal refrigerado à água, o qual se encontra detalhado em artigos anteriores [10,11], caracterização térmica da liga Sn-5%Pb para ajuste do teor de soluto através da obtenção da respectiva curva de resfriamento, análise química da liga para confirmação do teor de soluto por meio do processo de absorção atômica, obtenção dos perfis de temperatura para cinco posições de termopares (6,10,16, 34 e 54 mm) em relação à interface metal/molde e determinação das variáveis térmicas de solidificação (V L e T R ). Os procedimentos adotados para o cálculo dessas variáveis encontram-se especificados igualmente em trabalhos recentes [10,11].…”

Section: Materiais E Métodosunclassified

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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Study on stable delivery of charged uniform droplets for freeform fabrication of metal parts

Luo

Zhou

et al. 2011

Sci. China Technol. Sci.

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Electrostatic delivery of charged uniform metal droplets is a novel method to deposit metal parts with short process period and low cost. But the delivery process is unstable and delivery accuracy of charged droplets deteriorates because of actions of mutual interactions of closely charged droplets. A droplet generator with droplet charging and deflecting system has been established to find out the way for stably and accurately deflecting droplets. The parameters for generating uniform droplets were first studied. Then the droplet deflections and metal parts depositions with different charge methods were discussed. The results show that the unbalanced electrostatic repelling forces are the main factor to cause the unstable deflection of droplets. The droplets deflection distance can be predicted and controlled by balancing the repelling forces of charged droplets. The metal parts are stably deposited after combining the board charged pulse and substrate motion, indicating that the work can provide useful theoretical and experimental guide for droplet-based freeform fabrication. electrostatic delivery, uniform metal droplets, metal parts, freeform fabrication Citation: Luo J, Qi L H, Zhou J M, et al. Study on stable delivery of charged uniform droplets for freeform fabrication of metal parts.

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The columnar to equiaxed transition during the horizontal directional solidification of Sn–Pb alloys

Cited by 25 publications

References 29 publications

Influence of upward and horizontal growth direction on microstructure and microhardness of an unsteady-state directionally solidified Al-Cu-Si alloy

Influence of upward and horizontal growth direction on microstructure and microhardness of an unsteady-state directionally solidified Al-Cu-Si alloy

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

Study on stable delivery of charged uniform droplets for freeform fabrication of metal parts

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