CORRELATION BETWEEN MICROSTRUCTURE AND MECHANICAL AND CORROSION RESISTANCES OF A LEAD-FREE Sn-0,7%Cu SOLDER ALLOY
Sn-Cu alloys are promising alternatives to the replacement of Pb-containing solder alloys. However, the effects of the cooling rate on the solidification microstructures of these alloys and the corresponding influence on the mechanical and corrosion resistances are not well known. In the present s...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Associação Brasileira de Metalurgia, Materiais e Mineração
2014-12-01
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| Series: | Tecnologia em Metalurgia, Materiais e Mineração |
| Subjects: | |
| Online Access: | http://www.tecnologiammm.com.br/files/v11n4/v11n4a01.pdf |
| Summary: | Sn-Cu alloys are promising alternatives to the replacement of Pb-containing solder alloys. However, the effects of
the cooling rate on the solidification microstructures of these alloys and the corresponding influence on the mechanical
and corrosion resistances are not well known. In the present study, the transient directional solidification technique has
been used to obtain a Sn-0,7wt.%Cu ingot. The experimental results include: solidification thermal parameters (cooling
rate, Ṫ, growth rate, v, and metal/substrate heat transfer coefficient, hi
), cellular spacing, λc
, and primary dendritic arm
spacing, λ1
, corrosion rate, corrosion potential and polarization resistance and mechanical strength and ductility. The
results show a cellular/dendritic transition with eutectic cells prevailing for Ṫ< 0,9°C/s. Lower corrosion resistances have
been associated with dendritic regions compared with regions characterized by eutectic cells. In the interdendritic regions
extremely fine and fibrous Cu6
Sn5
intermetallic particles can be observed. |
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| ISSN: | 2176-1515 2176-1523 |