The Portevin–Le Chatelier effect: a review of experimental findings

Abstract

The Portevin-Le Chatelier (PLC) effect manifests itself as an unstable plastic flow during tensile tests of some dilute alloys under certain regimes of strain rate and temperature. The plastic strain becomes localized in the form of bands which move along a specimen gauge in various ways as the PLC effect occurs. Because the localization of strain causes degradation of the inherent structural properties and surface quality of materials, understanding the effect is crucial for the effective use of alloys. The characteristic behaviors of localized strain bands and techniques commonly used to study the PLC effect are summarized in this review. A brief overview of experimental findings, the effect of material properties and test parameters on the PLC effect, and some discussion on the mechanisms of the effect are included. Tests for predicting the early failure of structural materials due to embrittlement induced by the PLC effect are also discussed.

Exploring educational immersive videogames: an empirical study with a 3D multimodal interaction prototype

“…Augmented Reality (AR) has been widely adopted for learning and training, especially with mobile applications enabling ubiquitous, collaborative, and situated learning Yilmaz 2016). Bringing computation to our personal space may improve the educational activity (Mann & Hrelja 2013) 4.…”

Evidence That Strain-Rate Softening Is Not Necessary for Material Instability Patterns

“…The curves for V ≤ 0.13 mm.s −1 show stress drops that "fall off" the trend, with fluctuations that seldom rise diminutively above the trend. These serrations are reminiscent of type C PLC serrations [24][25][26], which are produced by the nucleation of static localized deformation bands. In contrast, curves between V = 1.3 and 10 mm.s −1 exhibit (i) a pronounced periodicity of large serrations, (ii) many small serrations between large ones, and (iii) stresses that fluctuate around the general trend.…”

On the PLC Effect in a Particle Reinforced AA2017 Alloy

“…This leads to additional pinning on the macro-scale (i.e., pinning of the propagating band as opposed to pinning of individual dislocations). We note that the amplitude of stress-strain serrations may also be influenced by the stiffness of the testing device, by the geometry of the specimen and by the surface quality of the specimen [8,17,21,45]. Figure 4 shows the results of the (compressive) jump tests of both materials in the solution annealed condition (W).…”

“…The so-called "jerky" or "serrated" flow is one of the most distinctive examples of plastic instability in dilute alloys. It is commonly rationalized by the dynamic interactions between solute atoms and mobile dislocations, i.e., dynamic strain aging processes [1,[3][4][5][6]9,11,12,[14][15][16][17][18][19][20][21][22][23]. Early observations of this phenomenon trace back to Le Châtelier who observed stress serration in the plastic flow of mild steel at elevated temperatures [24].…”