The paper presents the results of a study on the microstructure and mechanical properties of a mediumcarbon steel (0.45 % C) processed by severe plastic deformation (SPD) via high-pressure torsion (HPT). Martensite quenching was first applied to the material, and then HPT processing was conducted at a temperature of 350°C. As a result, a nanocomposite type microstructure is formed: an ultrafine-grained (UFG) ferrite matrix with fine cementite particles located predominantly at the boundaries of ferrite grains. The processed steel is characterized by a high-strength state, with an ultimate tensile strength over 2500 MPa. Special attention is given to analysis of the thermal stability of the microstructure and properties of the steel after HPT processing in comparison with quenching. It is shown that the thermal stability of the UFG structure produced by HPT is visibly higher than that of quenchinginduced martensite. The origin of the enhanced strength and thermal stability of the UFG steel is discussed.

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This article is devoted to formation of a subject of engineering decision in intelligent system of development of production processes based on description of functional models of engineering capabilities upon decision making. A subject of design engineering decision is a complicated system including subsystems of various essence, which operate according to rules described by fizzy logics and study cases. Design engineering decision is formed as a consequence of combined operation of intelligent system modules: equipment selection module, tool selection module, and accessory selection module. Each module of design engineering decision is characterized by its unique properties of engineering design both at input and output of decision formation. Therefore, each module of intelligent system of development of production processes is considered as a complex system with inherent properties. The components of a given specific system, for instance, selection of metal cutting equipment, will be input parameters for specific system module. Output parameters of the system of selection of metal cutting equipment will be input parameters for the system of selection of cutting tools, etc.

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