Banca de DEFESA: JEVERTON LAUREANO PAIXÃO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : JEVERTON LAUREANO PAIXÃO
DATA : 17/07/2019
HORA: 08:00
LOCAL: Sala de aulas do PPGCEM
TÍTULO:

Influence of the Antimony additions on the Directionally Solidified Hypoeutectic Sn-52wt.%Bi alloy: Thermal Parameters, Microsctructures and Mechanical Resistance

PALAVRAS-CHAVES:

Solidification; Thermal Parameters; Sn-Bi-Sb alloys; Microstructure; Tensile Mechanical properties.

PÁGINAS: 99
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
RESUMO:

The search for sustainable and less toxic materials is a global trend and should draw even more attention in the coming years due to the new and current restrictions/directives of environmental agencies. Lead-free solder alloys used in the electronics industry are examples of this scenario. In this context the present investigation aims to establish correlations between the solidification thermal parameters (cooling rate-ṪL and growth rate-VL) and microstructural parameters (primary-λ1, secondary-λ2 and tertiary-λ3 dendritic; and fine λF and coarse-λC eutectic spacings) for the directionally solidified (DS) Sn-52wt.%Bi-1wt.%Sb and Sn-52wt.%Bi-2wt.%Sb alloys under transient heat flow conditions. A dendritic array was identified for the Sn-Bi-Sb alloys formed by a Sn-rich matrix with Bi precipitates at its core, surrounded by lamellar eutectic structures (Sn-rich+Bi-rich), Bi trifolis and fishbone-like eutectic. The significant fraction of eutectic mixture (Sn-rich+Bi-rich) in the Sn-Bi-Sb alloys induced the -1/4 and -1/2 exponents, proposed by Jackson and Hunt for eutectics, characterize the evolutions of λ1, λ3 and λ2, as a function of ṪL and VL, respectively. These exponents also characterized evolutions of λF and λC against ṪL and VL for the modified alloy containing 1wt.%Sb. Hall-Petch type correlations for Sn-Bi-Sb alloys displayed that additions of 1wt.% and 2wt.%Sb have beneficial effects on the ultimate tensile strength-σu and the yield tensile strength-σy, but does not affect ductility (elongation to fracture-δ). Sb additions did not modify the fracture mode of the Sn-52wt.%Bi alloy.

MEMBROS DA BANCA:
Presidente - 2345599 - BISMARCK LUIZ SILVA
Externo à Instituição - CLAUDIO ALVES DE SIQUEIRA FILHO - UFPB
Externo ao Programa - 1652765 - MAURÍCIO MHIRDAUI PERES