Relationships between microstructural and mechanical aging effects in eutectic PbSn and Pb-free solder alloy Sn3.9Ag0.6Cu are reported and compared. The room temperature aged Sn3.9Ag0.6Cu alloy continually age-softened, this softening correlated with the growth of relatively large tin-rich crystals. The aged Sn3.9Ag0.6Cu alloy initially age-softened, and the minimum flow strength was reached after one day at This softening correlated with the growth of relatively large tin-rich crystals and with the coarsening of particles. When aged at beyond one day the Sn3.9Ag0.6Cu alloy age-hardened, the hardening correlated with the dispersion of particles into tin-rich crystals which previously had not contained intermetallic precipitates.
Issue Section:
Technical Papers
Keywords:
tin alloys,
silver alloys,
copper alloys,
eutectic alloys,
ageing,
crystal microstructure,
softening,
dispersion hardening,
tensile testing,
quench hardening,
solders
Topics:
Alloys,
Solders,
Temperature,
Eutectic alloys,
Lead-free solders,
Tin,
Hardening,
Tensile strength
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.Copyright © 2004
by ASME
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