Portevin-Le Chatelier PLC Effect

A schematic illustration shows the temperature-dependent PLC effect as observed in metals (Fig. 4.55), which is closely related to yield-point phenomena. Such 

TEM observations of thin foils parallel to the primary (001) slip plane of the deformed samples show typical dislocation substructures for YCSZ in easy glide. The microstructure consists mostly of straight-edge dislocations and a few dislocation loops, as may be seen in Fig. 4.57. By means of the line-intercept technique, the average dislocation density was estimated to about 10 m .  

Following the approach of Gallardo-Lopez et al., one can evaluate several properties for the PLC. Assume the waiting time for pinning the dislocations, tw, is  

Further assume that the flight time to the next obstacle is negligible. Let the concentration of the yttrium defects be c, each defect occupies c/a atomic sites in the slip plane, where the lattice spacing is a. The average distance between the obstacles is  

This is the ratio of the mean free path with the waiting time [21]. 

---

Fig. 4.55 The Portevin-Le Chatelier (PLC) effect. The influence of temperature on the appearance of a stress-strain curve under tension [7]...

---