Study on Dynamic Strain Aging Phenomenon of AZ91D Magnesium Alloy

Abstract

Tensile experiment of AZ91D magnesium alloy was carried out and serrated flow was apparent throughout the deformation history. Dynamic strain aging (DSA) occurs when the AZ91D magnesium alloy treated by solid solution treatment has been deformed at a set range of strain rates (1.11×10-4 s-1 to1.67×10-3 s-1) and a certain range temperatures (248 K to 423 K). The critical plastic strain εc was observed to increase with increasing strain rates but decrease with increasing temperature. The diffusing activation energy of solute atoms during the DSA occurring in AZ91D magnesium alloy is 140.8 kJ/mol by calculating, which is correspondence match with the diffusing activation energy of Al solute atoms in Mg matrix. Therefore, the micro-mechanism of DSA in the alloy is believed that the Al atoms in solid solution gather around dislocations to form Cottrell solute atmospheres by vacant diffusion and then pin the moving dislocations.

Theoretical insights into the Peierls plasticity in SrTiO3 ceramics via dislocation remodelling

“…The method in this paper also handles the interaction between dislocations and vacancies, which the traditional GSF approach fails to deal with. It is widely believed that point defect usually shows a pinning effect on dislocation and accordingly, reduces the dislocation mobility [36][37][38][39][40][41] . However, the calculation based on our model indicates that oxygen vacancies in SrTiO 3 can reduce the average misfit energy and the Peierls stress, contributing to the nucleation and activation of 〈110〉{110} edge dislocation.…”