THE INFLUENCE OF THERMAL VARIABLES OF SOLIDIFICATION ON THE MICROSTRUCTURE, HARDNESS AND MICROHARDNESS OF CU-8.5 WT% SN ALLOY

Ano: 2019

Instituições de ensino: Instituto Federal de Educação, Ciência e Tecnologia de São Paulo, Instituto Federal de Educação, Ciência e Tecnologia de São Paulo, Instituto Federal de Educação, Ciência e Tecnologia de São Paulo, Instituto Federal de Educação, Ciência e Tecnologia de São Paulo, Instituto Federal de Educação, Ciência e Tecnologia de São Paulo, Faculdade de Tecnologia Termomecanica, Instituto de Pesquisas Energéticas e Nucleares, Escola Politécnica da Universidade de São Paulo

Idioma: Ingles

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Resumo

The Cu-8.5wt% Sn alloy is similar to the UNS C51200 phosphor bronze, a material commonly used in the manufacture of machine elements and electrical contacts. Concomitantly with the solidification of this bronze occurs the formation of a eutectoid mixture (detrimental to subsequent forming processes). In this study was analyzed the influence of the thermal variables of solidification on the microstructure and the (micro)hardness of Cu-8.5wt% Sn alloy. The unidirectional solidification technique was used for the acquisition of thermal data and metallographic analysis was performed with the use of optical microscopy to characterize the microstructure of the material as well as to measure the dendrite arm spacing. Hardness tests were performed on samples from the columnar zone of the casting: six longitudinal samples and six transverse ones. The results showed that the (micro)hardness of the material tends to decrease as the dendrite arm spacing increases, as the tip growth rate decreases or as the cooling rate decreases. There is also a slight decrease in the amount of eutectoid mixture toward locations with higher tip cooling rate.

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