Papers by Author: V.I. Bulanov

Abstract: One of the problems of powder metallurgy still remaining is the problem of billets shrinkage at sintering. Introduction of a small impurity coating consisting of a very thin layer of the particles on the basic powder is a known method of compacting at sintering of powder materials. The mathematical modeling of such a process encounters ambiguity some issues of the sintering theory of metal powders, therefore forcedly leans on experiments. A mathematical model of powder metal sintering with nano- and microadditives is presented.

Abstract: The major problem of a powder material authority – the prediction of structural-phase composition in the production of new multicomponent materials by means of the mathematical description and making of the computer software for homogenization processes modeling in the binary metal-metal systems is solved. The objects of study are processes of nanopowders homogenization in solid-state metals nanosystems of the transition elements such as Fe-Mo, Fe-Cu, Fe-Ni, Fe-Cr. A complex theoretical and experimental study of homogeni¬zation processes in solid-state nanosystems is carried out. The analytical dependences of degree of homogenization on time and temperatures of the sintering process are established, the coefficients of mutual diffusion in systems are calculated, physical and chemical model of homogenization are offered, means of the computer nu¬merical analysis with visualization of the studied processes are created. The estimation of convergence of the numerical methods employed are carried out, the accuracy of calculations is determined, estimated calcula¬tions for considered systems are carried out. The obtained results will allow the reduction in the number of real experiments in the creation of new mate¬rials with required properties.

Abstract: Equations for an estimation of hardness and durability of materials of particles of iron powders in various zones are received. The opportunity of reception of materials with physicomechanical properties above separate zones of particles is shown. By development of technological processes of manufacturing sintered details with demanded physicomechanical properties it is necessary to know the physical characteristics of particles of an initial material, and sintered ensemble with them and their possible limiting values. However, definition of separate mechanical characteristics of particles is impossible because of their small sizes and complex form. Authors attempt to define strength and fluidity of various zones of particles of iron powders and sintered materials on their basis, using a method of microhardness testing.

Abstract: Reduction and sintering are complicated processes demanding use of mathematical modelling - consolidation of multicomponent materials. The most representative of them are products formed during consolidation during sintering of powders. They have common physical and chemical characteristics both from the viewpoint of initial (multicomponent) materials, and from the viewpoint of technological parameters. Such processes simultaneously involve both the reduction and the sintering with simultaneous consolidation of particles into materials. The sintering of powders of crystals is a flexible and effective way of production of polycrystalline composite materials with a given structure and properties. In this paper a mathematical model of the process of sintering suggested by us is considered.