Automatic adjustment method to fit T¿LOG(T/¿0) scaling for time evolution thermal depending properties of nanocristalline iron

Abstract

In many forming processes the evolution of the material properties evolves with time and changes as temperature varies, forcing the use of a time-dependent thermomechanical computational model to simulate those processes. If the property under study could be described as a collectivity of microentities jumping over a certain distribution of energy barriers from one metastable state to another, then the whole behaviour of the material property follows a T·Ln(t/0) scaling. The use of T·Ln(t/0) as an integration variable could be employed to simplify the computational procedure. Also this scaling description allows to extrapolate the time evolution behaviour at times (or speeds) that are experimentally inaccessible. From this scaling it is also possible to determine the attempt period 0, needed by the computational model. All the properties described by the Arrhenius Law could be scaled by this method. In the present work the results of appling this scaling method to the hardness of a nanocrystalline iron powder with several annealing treatments are presented, and an algorithm for automatic adjustment of a T·Ln(t/0) scaling is tested.