Artículos de revistas
Cellular growth during the transient directional solidification of Zn-rich Zn-Cu monophasic and peritectic alloys
Registro en:
Journal Of Physics And Chemistry Of Solids. Pergamon-elsevier Science Ltd, v. 73, n. 9, n. 1173, n. 1181, 2012.
0022-3697
WOS:000307035200023
10.1016/j.jpcs.2012.05.014
Autor
Brito, C
Siqueira, CA
Spinelli, JE
Garcia, A
Institución
Resumen
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Zn-Cu alloys located in the monophasic and hypoperitectic ranges of compositions of Zn-rich Zn-Cu alloys were directionally solidified under unsteady-state heat flow conditions. The experimental cooling curves allow solidification thermal parameters: tip cooling rate ((T) over dot), tip growth rate (V-L) and temperature gradient (G(L)) to be experimentally determined. The observed microstructural evolution of both alloys has shown that a regular cellular morphology prevails along the whole castings lengths. Only the regions very close to the cooled casting surface showed the presence of plate-like cells due to very high cooling rates (higher than 25 K/s). The cell spacing (lambda(c)) was measured along the castings lengths, and experimental correlations between lambda(c) and experimental solidification thermal parameters have been established. Power laws with -0.55 and -1.1 exponents expressing lambda(c) as a function of (T) over dot and V-L, respectively, were found to better represent the growth of cells under transient heat flow conditions for both alloys experimentally examined. The predictions furnished by the Hunt-Lu model underestimate the experimental cell spacings found for both alloys examined. It was shown that the proposed equations relating lambda(c) as a function of (T) over dot are able to represent both the steady-state and unsteady-state cellular growth of monophasic and peritectic Zn-rich Zn-Cu alloys. (C) 2012 Elsevier Ltd. All rights reserved. 73 9 1173 1181 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) FAEPEX-UNICAMP Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)