Revisiting the Applicability Question of G.V. Samsonov’s Activated Sintering Concept in Studying Deformation Processes of Powder Materials

• Published in: Russian journal of non-ferrous metals 2019-09, Vol.60 (5), p.549-554
• Main Authors: Dorofeyev, V. Yu, Sviridova, A. N., Kochkarova, Kh. S.
• Format: Article
• Language: English
• Subjects: Activated sintering; Activation energy; Additives; Chemistry and Materials Science; Chromium; Configuration management; Crystal lattices; Densification; Diffusion coefficient; Iron; Manganese; Materials Science; Meetings; Metallic Materials; Nickel; Plastic deformation; Plastic flow; Questions; Segregations; Self diffusion; Shrinkage; Sintering; Theory and Processes of Forming and Sintering of Powder Materials
• ISSN: 1067-8212; 1934-970X
• DOI: 10.3103/S1067821219050109

Some of Yu.G. Dorofeyev’s recollections about joint work and meetings with G.V. Samsonov, an outstanding materials science expert, are presented. Meetings in Yugoslavia, where G.V. Samsonov and M.M. Ristić, together with other world-famous scientists, developed the International Institute for the Science of Sintering, are of special importance. In the last years of his life, G.V. Samsonov proposed the concept of sintering activation by additives that act as electron acceptors and additionally contribute to the fraction of the ionic bond in the material. The possibility of applying this concept when developing activator additives, reducing the plastic deformation activation energy of powder materials based on iron, is considered. Sintering activation during the formation of stable electron configurations can be performed due to (i) accelerating grain-boundary heterodiffusion of the matrix material in the presence of segregations of the phase containing the activating microadditives (the W–Ni system), (ii) intensifying shrinkage during the plastic flow of the material matrix particles in the presence of segregation of phases containing the activating microadditive (the Fe–Ni, Fe–Co, Fe–Mn system), and (iii) an increase in the self-diffusion coefficient of host metal atoms due to the expansion of the occurrence region of a less closely packed crystal lattice (α phase) with the dissolution of the activating additive (the Fe–Mo system). The analysis of available information touching the prospects of using manganese and chromium as additives—densification activators—is presented. A decrease in the activation energy of densifying iron-based powder materials can be enabled when introducing manganese additives. Herewith, it is promising to apply diffusion saturation technology. The question of using chromium as the activator has no confirmatory answer and assumes the necessity of the additional investigation.