Precipitation kinetics in quenched and slowly cooled Pb–1.5wt% Sb alloy specimens

Abstract

Stress–strain characteristics of Pb–1.5wt% Sb alloy have been studied in the temperature range from 393 to 513K for both quenched and slowly cooled specimens. The coefficient of work hardening, wP; yield stress, sy; and fracture stress, sf ; of the quenched specimens were found to be higher than those of the slowly cooled specimens. These parameters of both types of specimens were generally found to decrease with increasing deformation temperature, showing two stages around the transformation temperature (443 K). In the first stage the rate of change of these parameters was found to increase with increasing deformation temperature, while it decreases in the second stage. The ductility—fracture strain percent of this alloy exhibited a minimum value at this temperature. The calculated slip distance of the moving dislocations showed a small variation in the temperature range below 443K while a considerable change in slip distance was observed above this temperature for both quenched and slowly cooled specimens. The two observed temperature regions below and above 443K may characterize a point of dislocation intersection mechanisms activated with 0:3 and 0.6 eV for the two regions, respectively. The microstructure of the samples under investigation was examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. r 2004 Elsevier B.V. All rights reserved.