Kinetics of precipitation hardening in Pb–0.08 wt.%Ca–x wt.%Sn alloys by in situ resistivity measurements

The effects of tin content and annealing temperature on the transformation sequences of Pb–0.08 wt.%Ca–x wt.%Sn supersaturated alloys (with x = 0.6, 1.2 and 2.0%) have been firstly studied from TEM observations and hardness measurements. Secondly, the age-hardening kinetics of these ternary alloys during isothermal holdings have been characterized by electrical resistivity measurements. In particular, it appeared that increase of tin content both delayed the main metallurgical stages and is accompanied by suppression of the first discontinuous reactions of ageing when the Sn/Ca ratio value is above 9. Moreover, the ageing kinetics are accelerated when increasing the annealing temperature because of the solute diffusion activation.