Investigation of PLC bands with optical techniques

Abstract The Portevin–Le Châtelier effect is an interesting phenomenon that afflicts the deformation working of ductile alloys. Characteristic of this effect are the so-called PLC bands, regions of concentrated deformation that usually follow each other in a regular manner. An optical extensometer is here presented as a new measurement set-up for the investigation of these PLC bands. The optical extensometer has been employed during tensile deformation of Al–3wt.%Mg specimens and the propagation of type-B PLC bands has been detected and its velocity measured. A real-time analysis of data has been realized up to 250 scans/s, it permits to locate a deformation as soon as it emerges. This will soon make it possible to track their propagation by means of an optical sensor.