observation of portevin _ le chatelier deformation mechanism in metals and alloys

Portevin-Le chatelier effect

Aluminum subjected to smooth mechanical loading does not often deform in a correspondingly smooth manner. Typically it deforms inhomogeneously through the propagation of deformation fronts that slowly traverse the sample. These are called Portevin-Le Chatelier fronts; what determines their velocity has been somewhat mysterious. We present a phenomenological theory for deformation fronts that ce...

Portevin–Le Chatelier effect in an aluminum alloy

Time-resolved strain mapping measurements of individual Portevin–Le Chatelier deformation bands

A technique based on high-speed digital photography and image correlation for direct whole-field strain mapping of Portevin–Le Chatelier deformation bands is described. Results for a type B band show that the deformation band was formed within a few milliseconds and remained stationary as no motion of the band was detected. 2005 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.

Chaotic and power law states in the Portevin - Le Chatelier effect

– Recent studies on the Portevin Le Chatelier effect report an intriguing crossover phenomenon from a low dimensional chaotic to an infinite dimensional scale invariant power law regime in experiments on CuAl single crystals and AlMg polycrystals, as a function of strain rate. We devise a fully dynamical model which reproduces these results. At low and medium strain rates, the model is chaotic ...

Construction of Deformation - Mechanism Maps for Metals and Solid Solution Alloys a New Approach

A new approach has been introduced to construct deformation-mechanism maps for metals and solid solution alloys. For this purpose two computer programs named DEFOR and GRAPH have been written in BASIC to be run on IBM compatible personal computers. Using these programs, deformation - mechanism maps for a number of pure metals and a solid solution alloy (Ti-6wt% Al) have been plotted and effects...

Effect of Heat Treatment on the Portevin-Le Chatelier Effect of Al-2.5%Mg Alloy

An experimental study is presented on the effect of microstructural change on the Portevin-Le Chatelier effect behaviour of Al-2.5%Mg alloy. Tensile tests are performed on the as received and heat treated (at 400 oC for 16 hours) samples for a wide range of strain rates. The serrations observed in the stress-time curve are investigated from statistical analysis point of view. Microstructures of...