The microstructure and selected mechanical properties of sintered, Fe-Al graded materials
Stanisław Lipiński, Tomasz Durejko
Quarterly No. 2, 2010 pages 165-169
DOI:
keywords: powder metallurgy, graded Fe-Al materials, sintering under periodically changing load
abstract Nowadays, high efforts in the research are focused on modern, ergonomic and multifunctional constructions, which require an application of advanced materials, appropriate for extreme exploitation conditions. Thus, there is a need for the use of innovative, unconventional materials, and the application of advanced techniques. In this work the results of the research of sintered, graded Fe-Al materials are presented, with continuous and discrete change of chemical composition. The materials were produced by the laminar batch preparation of the matrix, by the use of the numerically controlled batch head. Cold compressed compacts were sintered under the periodically changing load, and then were annealing at the temperature of 1200°C in the inert gas atmosphere. The structure analysis of the sintered samples were performed by using X-ray diffraction technique. It was observed that the phase transformations and diffusion process taking place during the sintering cause both the chemical and phase structure standardization in a given graded zone. The distribution of micro hardness and the analysis of the chemical composition have shown that both in the continuous and discrete system a strong increase of the micro hardness values is accompanied by the increase of the oxygen content near the Fe50Al surface, what is an evidence for a larger Al2O3 participation. The fluctuation of the chemical composition is connected with the application of the periodically changing load, what leads to the segregation of the alumina in the surface region. The properties arising from the chemical composition are changing in a quasi linear mode, what confirms that these materials fulfill the presuppositions imposed on the graded materials.