E. Hilali et al., Structural hardening of lead-cadmium (tin-silver) alloys for battery's grids. I. Lead-cadmium alloys., ANN CHIM-SC, 24(2), 1999, pp. 135-143
The reequilibration of supersatured Pb-Cd alloys was studied by different e
xperimental methods: hardness measurements, optical and electron microscopy
, electron microprobe. Two structural states were considered: as-cast alloy
s, rehomogenised alloys. The Cd contents were 1, 1.5, 2 and 3.2 weight%. Th
e explored temperatures were 20 and 80 degrees C. This last temperature cor
responds to the curing temperature of battery's grids and to the highest op
erating temperature. The evolution of the quenched structure towards the eq
uilibrium state was studied for the time range one minute to one year. The
corresponding aging is characterized by a continuous precipitation and a di
scontinuous transformation. The hardening process is followed by an overagi
ng which consists of a discontinuous transformation with a reprecipitation
of the Cd from the fine hardening precipitates of the same phase.