Interconnection of thermal parameters, microstructure, macrosegregation and microhardness of unidirectionally solidified Zn-rich Zn-Ag peritectic alloys

Autor(es)

Dias, Marcelino ^[1] ; Brito, Crystopher ^[1] ; Bertelli, Felipe ^[1] ; Rocha, Otavio L. ^[2] ; Garcia, Amauri ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, UNICAMP, Dept Mfg & Mat Engn, BR-13083970 Campinas, SP - Brazil

^[2] IFPA, Fed Inst Educ Sci & Technol Para, BR-66093020 Belem, Para - Brazil

• Tipo de documento: Artigo Científico
• Fonte: MATERIALS & DESIGN; v. 63, p. 848-855, NOV 2014.
• Citações Web of Science: 5

Resumo

In this work, the microstructural evolution of Zn-3.2 wt%Ag (hypoperitectic) and Zn-8 wt%Ag (hyperperitectic) alloys during transient unidirectional solidification is investigated. The experimental results include solidification thermal parameters such as the growth rate (V-L), thermal gradient (G(L)) and tip cooling rate (T), which are related to the microstructural interphase spacing (lambda) by proposed experimental growth laws. It is shown that, the classical lamellar eutectic growth law lambda V-2 = constant, applies to the growth of the peritectic Zn-Ag alloys examined, despite the different values of the constant associated with each alloy composition. In contrast, it is shown that identical functions of the form lambda = constant (G(L)) (14)(V-L) (1/8), and lambda = constant (T-1/3) can be applied to both alloys examined. Positive solute macrosegregation was observed in regions close to the bottom of the castings. The dependence of microhardness (HV) on the length scale of the microstructures (including that of a single phase Zn 0.8 wt%Ag alloy: lambda(C) cellular spacing) is examined. An experimental Hall-Petch type power law is proposed relating the resulting microhardness to lambda(C) for the single phase alloy, and despite the segregation profiles and the alloying differences of the hypoperitectic and hyperperitectic alloys, the average microhardnesses of these alloys is shown to be essentially constant and similar along the castings lengths. (C) 2014 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 12/16328-2 - Correlação entre Microestruturas de Solidificação e Propriedades Mecânicas e Tribológicas de Ligas Al-Sn-Cu e Al-Sn-Si
• Beneficiário: Felipe Bertelli
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/09267-0 - Evolução microestrutural na solidificação transitória de ligas monofásicas e peritéticas Sn-Sb (e Sn-Sb-X) para soldagem e em camadas interfaciais solda/substrato
• Beneficiário: José Marcelino da Silva Dias Filho
• Linha de fomento: Bolsas no Brasil - Doutorado
• Processo FAPESP: 12/08494-0 - Parâmetros Térmicos e Microestruturais na Solidificação Transitória de Ligas Al-Mg e Al-Mg-Si e Correlação com Resistências Mecânica e à Corrosão
• Beneficiário: Crystopher Cardoso de Brito
• Linha de fomento: Bolsas no Brasil - Doutorado