The Portevin-Le Chatelier effect in nickel-base superalloys: Origins, consequences and comparison to strain ageing in other alloy systems

Portevin–Le Chatelier effect in an aluminum alloy

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...

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...

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 ...

Strain induced abnormal grain growth in nickel base superalloys

Under certain circumstances abnormal grain growth occurs in Nickel base superalloys during thermomechanical forming. Second phase particles are involved in the phenomenon, since they obviously do not hinder the motion of some boundaries, but the key parameter is here the stored energy difference between adjacent grains. It induces an additional driving force for grain boundary migration that ma...