Interaction of Hydrogenated Layers in Iron Powders

Abstract

We study the formation of hydrogen-saturated zones in the course of polymorphic transformations in iron powders and demonstrate the possibility of nucleation of H-layers in small volumes of the metal (less than 0.1 mm3). It is shown that the H-layers interact with powdered iron in the process of thermocyclic sintering in gaseous hydrogen, a significant role in this process is played by the grain size of the powder, and the parameters of thermal cycling significantly affect the final structure and density of sintered specimens. The structure of specimens sintered in the course of thermal cycling fundamentally differ from the structure of specimens sintered by using traditional methods. Thus, this structure is fibrous and characterized by higher levels of strength and porosity than the traditional structure. It is also shown that the porosity of specimens can be controlled by changing the parameters of the process.