Correlation Between Unsteady-state Solidification Conditions, Dendrite Spacings, And Mechanical Properties Of Ai-cu Alloys

The wide range of operational conditions existing in foundry and casting processes generates as a direct consequence a diversity of solidification microstructures. Structural parameters such as grain size and interdendritic spacings are strongly influenced by the thermal behavior of the metal/mold system during solidification, imposing, as a consequence, a close correlation between this system and the resulting microstructure. Mechanical properties depend on the microstructural arrangement defined during solidification. Expressions correlating the mechanical behavior with microstructure parameters should be useful for future planning of solidification conditions in terms of a determined level of mechanical strength, which is intended to be attained. In the present work, analytical expressions have been developed describing thermal gradients and tip growth rate during one-dimensional unsteadystate solidification of alloys. Experimental results concerning the solidification of Al-4.5 \vt pet Cu and Al-15 wt pet Cu alloys and dendritic growth models have permitted the establishment of general expressions correlating microstructure dendrite spacings with solidification processing variables. The correlation of these expressions with experimental equations relating mechanical properties and dendrite spacings provides an insight into the preprogramming of solidification in terms of casting mechanical properties.311231673178Durman, M., (1998) Z Metallkd, 6, pp. 417-423Seah, K.H.W., Hemanth, J., Sharma, S.C., (1998) J. Mater. Sei., 33, pp. 23-28Savans, M.A., Altintas, S., (1993) J. Mater. Sei., 28, pp. 1775-1782Hall, E.O., (1951) Proc. Pliys. Soc., 71, pp. 747-752Fetch, N.J., (1953) J. Iron Steel Inst., 174, pp. 25-31Bouchard, D., Kirkaldy, J.S., (1996) Metall. Mater. Trans. B, 27, pp. 101-113Kirkaldy, J.S., Venugopalan, D., (1989) Scripta Metall., 23, pp. 1603-1608Kurz, W., Fisher, D.J., (1981) Ada Metall., 29, pp. 11-20Bouchard, D., Kirkaldy, J.S., (1997) Metall. Mater. Trans. B, 28, pp. 651-663Hunt, J.D., Lu, S.Z., (1996) Metall. Mater. Trans. a, 27, pp. 611-623Feng, J., Huang, W.D., Lin, X., Pan, Q.Y., Li, T., Zhou, Y.H., (1999) J. Cryst. Growth, 197, pp. 393-395Mullins, W.A.V., Sekerka, R.F., (1964) J. Appl. Phys., 35, pp. 444-451Garcia, A., Prates, M., (1978) Metall. Trans. B, 9, pp. 449-457Garcia, A., Clyne, T.W., Prates, M., (1979) Metall. Trans. B, 10, pp. 85-92Mondolfo, L.F., (1976) Aluminum Alloy-Structure and Properties, 1st Ed., Butterworth and Co, LondonBerry, J.T., (1970) AFS Trans., 78, pp. 421-428Taha, M.A., El-Mahallawy, N.A., Assar, A.W.M., Hammouda, R.M., (1992) J. Mater. Sei., 27, pp. 3467-3473Spim, J.A., Garcia, A., (2000) Mater. Sei. Eng. a, 277, pp. 198-205(1995) ASTM E 8M-Standard Test Methods for Tension Testing of Metallic Materials, ASTM, Philadelphia, P

Plate-like Cell Growth During Directional Solidification Of A Zn-20wt%sn High-temperature Lead-free Solder Alloy

Although Zn-Sn alloys have suitable features for high temperature solders, as for example the absence of intermetallic compounds (IMCs) and relatively high melting temperatures, the control of the scale of the microstructure by adequate pre-programming of the solidification thermal parameters remains still a task to be accomplished. The present study focuses on the interrelation among hardness, microstructure features/segregation and solidification thermal parameters. An upward directional transient solidification apparatus was used in order to permit samples along a range of cooling rates to be obtained for such evaluation. The entire Zn-20wt%Sn alloy casting is characterized by a two-phase alternated structure, which resembles the morphology of a lamellar eutectic. Experimental growth laws having -1/2 and -1/4 exponents are proposed relating the interphase spacing to the growth rate and the cooling rate, respectively. The morphology and size of the Zn-rich plate-like cells, as well as the macrosegregation pattern are shown to affect the hardness. © 2013 Elsevier B.V.18212936Suganuma, K., Kim, S., Kim, K., (2009) JOM, 61, pp. 64-71Osório, W.R., Peixoto, L.C., Garcia, L.R., Mangelinck-Noël, N., Garcia, A., (2013) J. Alloys Compd., 572, pp. 97-106Chen, J., Shen, J., Min, D., Peng, C.F., (2009) J. Mater. Sci.: Mater. Electron., 20, pp. 1112-1117Li, Y., Moon, K.-S., Wong, C.P., (2005) Science, 308, pp. 1419-1420Çadirli, E., Böyük, U., Engin, S., Kaya, H., Marasli, N., Ülgen, A., (2009) J. Alloys Compd., 486, pp. 199-206Garcia, L.R., Osório, W.R., Peixoto, L.C., Garcia, A., (2009) J. Electron. Mater., 38, pp. 2405-2414Ahmido, A., Sabbar, A., Zouihri, H., Dakhsi, K., Guedira, F., Serghini-Idrissi, M., El Hajjaji, S., (2011) Mater. Sci. Eng. B, 176, pp. 1032-1036Wang, I., Duh, J., Cheng, C., Wang, J., (2012) Mater. Sci. Eng. B, 177, pp. 278-282Sharif, A., Chan, Y.C., (2004) Mater. Sci. Eng. B, 106, pp. 126-131Zeng, G., McDonald, S., Nogita, K., (2012) Microelectron. Reliab., 52, pp. 1306-1322Lee, J.E., Kim, K.S., Suganuma, K., Takenaka, J., Hagio, K., (2005) Mater. Trans., pp. 2413-2418Chidambaram, V., Hattel, J., Hald, J., (2011) Microelectron. Eng., 88, pp. 981-989Che, F.X., Zhu, W.H., Poh, E.S.W., Zhang, X.W., Zhang, X.R., (2010) J. Alloys Compd., 507, pp. 215-224Wang, M., Wang, J., Feng, H., Ke, W., (2012) Corros. Sci., 63, pp. 20-28Montesperelli, G., Rapone, M., Nanni, F., Travaglia, P., Riani, P., Marazza, R., (2008) Mater. Corros., 59, pp. 662-669Liu, X., Huang, M., Zhao, Y., Wu, C.M.L., Wang, L., (2010) J. Alloys Compd., 492, pp. 433-438Lee, J.E., Kim, K.S., Suganuma, K., Inoue, M., Izuta, G., (2007) Mater. Trans., 48, pp. 584-593Ferreira, I.L., Spinelli, J.E., Pires, J.C., Garcia, A., (2005) Mater. Sci. Eng. A, 408, pp. 317-325Canté, M.V., Spinelli, J.E., Ferreira, I.L., Cheung, N., Garcia, A., (2008) Metall. Mater. Trans. A, 39, pp. 1712-1726Rosa, D.M., Spinelli, J.E., Ferreira, I.L., Garcia, A., (2008) Metall. Mater. Trans. A, 39, pp. 2161-2174Gunduz, M., Çardili, E., (2002) Mater. Sci. Eng. A, 327, pp. 167-185Goulart, P.R., Cruz, K.S., Spinelli, J.E., Ferreira, I.L., Cheung, N., Garcia, A., (2009) J. Alloys Compd., 470, pp. 589-599Ma, D., Li, Y., Ng, S.C., Jones, H., (2000) Acta Mater., 48, pp. 419-431Ma, D., Li, Y., Li, S.C.N.G., Jones, H., (2001) Sci. Technol. Adv. Mater., 2, pp. 127-130Xu, W., Feng, Y.P., Li, Y., Zhang, G.D., Li, Z.Y., (2002) Acta Mater., 50, pp. 183-193Xu, W., Feng, Y.P., Li, Y., Li, Z.Y., (2004) Mater. Sci. Eng. A, 373, pp. 139-145Matsugi, K., Sasaki, G., Yanagisawa, O., Kumagai, Y., Fujii, K., (2007) Mater. Trans., 48, pp. 1105-1112Mahmudi, R., Eslami, M., (2011) J. Mater. Sci.: Mater. Electron., 22, pp. 1168-1172Jackson, K.A., Hunt, J.D., (1966) Trans. Metall. Soc. AIME, 236, pp. 1129-1142Ferreira, I.L., Santos, C.A., Voller, V.R., Garcia, A., (2004) Metall. Mater. Trans. B, 35, pp. 285-297Silva, B., Garcia, A., Spinelli, J.E., (2012) Mater. Lett., 89, pp. 291-295Brito, C., Siqueira, C.A., Spinelli, J.E., Garcia, A., (2012) Mater. Lett., 80, pp. 106-10

Analysis of factors which influence the formation of surface defects in ingots

20.00; Translated from Portuguese (ABM 38. Ann. Cong. Sao Paulo (PT) Jul 1983 v. 4 p. 303-324)SIGLEAvailable from British Library Document Supply Centre- DSC:9022.06(BISI-Trans--25269)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Theoretical - Experimental Analysis of Cellular and Primary Dendritic Spacings during Unidirectional Solidification of Sn-Pb Alloys

Structural parameters as grain size, dendritic and cellular spacings, segregated products, porosity and other phases are strongly influenced by the thermal behavior of the metal/mold system during solidification, imposing a close correlation between this and the resulting microstructure. Several unidirectional solidification studies with the objective of characterizing cellular and dendritic spacings have been developed in large scale involving solidification in steady-state heat flow. The main objective of this work is to determine the thermal solidification parameters during the cellular/dendritic transition as well as to compare theoretical models that predict cellular and primary dendritic spacings with experimental results for solidification situations in unsteady-state heat flow. Experiments were carried out in a water cooled unidirectional solidification apparatus and dilute alloys of the Sn-Pb system were used (Sn 1.5wt%Pb, Sn 2.5wt%Pb and Sn 5wt%Pb). The upper limit of the Hunt-Lu cellular growth model closely matched the experimental spacings. The lower limit calculated with the Hunt-Lu dendritic model best generated the experimental results. The cellular/dendritic transition was observed to occur for the Sn 2.5wt%Pb alloy over a range of analytical cooling rates from 0.28 K/s to 1.8 K/s