Multilevel analysis of deformation and structure formation processes in powdered iron aluminide products obtained by different technological schemes of direct powder forging

Abstract

A multilevel analysis of deformation and structure formation processes was carried out on powdered iron aluminide products obtained by different DPF technological schemes. At the macroscopic level, the analysis was carried out using rheological models of porous body compaction. The compaction curves are conventionally divided into three stages: at the first stage, the deformed volume decreases due to the deformation of the holder, at the second stage—due to the compaction of the porous workpiece, at the third stage—due to the plastic deformation of the dense workpiece realized due to the formation of a flake. When the compaction temperature and deformation pattern change, the staged compaction is maintained. At the meso level, the distribution of stresses and strains in the moulds and the kinetics of their changes during compaction were analysed by the finite element method. To predict the effect of structural changes on the complex of physical and mechanical properties, local processes of structure formation are analysed. It was established that the effect of porosity on electrical resistance and yield strength should be determined by the volume content of pores, consider planar pores, which are a characteristic feature of hot forging powder technology. During the strength analysis, special attention is paid to the areas around the triple joints, where defects of the maximum size are formed. The fracture toughness parameters and fracture pattern are sensitive to the presence of segregation clusters in the boundary region.