Banca de DEFESA: LIDIANE SILVA RAMOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : LIDIANE SILVA RAMOS
DATA : 15/08/2019
HORA: 14:00
LOCAL: Sala de aulas do PPGCEM
TÍTULO:

Directional solidification of the eutectic Sn-9wt.%Zn alloy: Inter-relations of microstructure, thermal parameters and mechanical properties

PALAVRAS-CHAVES:

Directional Solidification; Thermal Parameters; Sn-Zn alloys; Microstructure; Mechanical properties.

PÁGINAS: 84
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Materiais e Metalúrgica
RESUMO:

The manufacture and use of electronic devices have grown every year in the various applications, however the sustainable control of the materials used still needs to advance. It’s at this moment that lead-free solder alloys enter as alternatives to sustainable materials in the electronics industry. In this context, the present investigation aims to study the growth eutectic in the Sn-9wt%Zn alloy solidified on different substrates (steel and copper). Microstructural features (phases, morphologies, distribution and microstructural scale such as eutectic and cellular spacings), thermal parameters (growth rate-VE and cooling rate-ṪE), experimental growth laws and tensile mechanical properties (ultimate tensile strength-σu, yield tensile strength-σY and elongation-to-fracture-δ) have been discussed. Sn-Zn alloy castings displayed a microstructure with eutectic colonies formed by Zn-rich phase, α-Zn, dispersed with two morphologies, globular-λg and needles-λn, in the Sn-rich matrix. Considering two Sn-Zn ingots, it can be seen that for VE>1,38 mm/s e ṪE>4,75 °C/s values, a globular morphology prevails in the microstructure, while for VE<0,88 mm/s e ṪE<1,86°C/s values, α-Zn needles predominate. Higher mechanical resistance (σu and σY) and ductility (δ) values have been observed for refined structures in both Sn-Zn alloy castings. The fractographs revealed a mode of ductile fracture for the Sn-Zn ingots analyzed, with higher fraction of dimples.

MEMBROS DA BANCA:
Presidente - 2345599 - BISMARCK LUIZ SILVA
Externo ao Programa - 1938946 - NICOLAU APOENA CASTRO
Externo à Instituição - CRYSTOPHER CARDOSO DE BRITO - UNESP