In mid-1995 the N. [~. Bauman Moscow State Engineering University celebrated its 165th anniversary. At the beginning of this century the university gave birth to many scientific schools and investigations. among which a central place belonged to the Moscow School of Metallurgy (1909), which determined in many respects the development of materials science, methods of heat treatment of materials, and their use in industry.For 87 years the ideas of metal science have been developed in the Department of Materials Science and Heat Treatment. It has always been a leader in the countrT's research in the field of metallic materials and maintains this position at the present time, which can be inferred from the results in the works presented below.The interests of the Department cover creation of new metallic alloys, investigation of the effect of heat treatment on the structure and properties of structural steels, creation of new methods of physicochemical treatment, investigation of corrosion processes, and many other topics. Austenitic dispersion-hardening alloy 36NKhTYuM8 is well known as a nonmagnetic corrosion-resistant and heat-resistant spring material having quite good technological ductility (after quenching) and a high yield strength after aging (oo 002 = 930 -950 N/ram2). It is used for the production of complicated and critical elastic members. There are data on the possibility of a certain improvement in the adaptability to manufacture and the operating properties of the alloy. The present work concerns the possibility of rapid quenching with the use of electric-contact healing for alloy 36NKhTYuM8.It is known [ I -3] that conventional quenching of alloy 36NKhTYuM8 with heating to 1000-1050°C does not provide complete dissolution of the excess Laves Fe~Mo phase. The particles of this phase retained in the structure of the quenched alloy decrease its technological ductility, prevent full realization of the effect of dispersion hardening in aging, and play the role of stress concentrators that decrease the fatigue strength of the material under cyclic loads. Nevertheless, the alloy is not quenched from a higher temperature due to its susceptibility to grain growth.Under these conditions, it seems expedient to turn to rapid heating for quenching the alloy. In rapid heating combined with short-term holds the alloy can be superheated (above the conventionally used quenching temperatures). which should intensify the diffusion and thus create conditions for dissolution of a larger amount of the excess phase with retention of the fine-grain structure. For thin-sheet and wire semi-finished products of the spring alloy the most efficient method of rapid heating is electric-current contact heating [4]. As applied to dispersion-hardening alloys, this method has been used in [4] for aging and in [5] for rapid recrystallization annealing without selective aging of the alloy in the heating process; in both cases the resulting material had a fine-grain structure.We investigated ~ the effects of the regimes of rapid quenchi...

The use of rapid electrocontact heating (by an electric current) in quenching dispersion-hardening alloys opens new prospects for substantial improvement of their properties by providing the requisite degree of dissolution of the excess phases with retention of the fine-grained structure of the supersaturated solid solution, which is difficult to attain under the conditions of conventional heating. The advantage of such quenching is connected with the possibility of short-term superheating of the alloy above the temperature of heating for quenching conventionally used. Therefore, such a Ixeala-nent is expedient foremost for alloys that contain poorly soluble excess phases. The present work concerns the role of the heating rate for quenching in formation of the phase composition and slxucture of quenched dispersion-hardening spring alloy 36NKhTYuM8.The composition of dispersion-hardening spring alloy 36NKhTYuM8 has been designed to employ the reinforcing effect of segregation of two intermetallic phases in aging, namely, a y'-phase of the Ni3(Ti, AI) type and a Laves phase ofthe Fe2Mo type [1].The main difficulty in quenching alloy 36NKhTYuM8 consists in dissolution of the poorly soluble Laves phase. The conventional furnace heating (in a protective atmosphere) to 1000-1050~ used in quenching virtually cannot dissolve the excess Laves phase contained in the alloy in any as-received state, and a higher temperature of heating for quenching is not used due to the susceptibility of the alloy to grainThe use of rapid electrocontact heating for quenching alloy 36NKhTYuM8 turned out to be very effective precisely because of the greater dissolution of the excess Laves phase as compared to conventional furnace heating [2]. It has been shown that heating at a rate v h = 300 K/sec to 1200~ with a 6-9-sec hold almost halves the content of the excess Laves phase relative to the initial content with retention of the finegrained structure (d< 15 mm). It has been shown in [2] that rapid quenching is characterized by an unusual kinetics of the dissolution of the excess Laves phase, because the predominant part of this phase dissolves precisely in the heating stage. The dissolution is especially intense if the alloy has been deformed before quenching. Thus, an increase in the heating rate in quenching the alloy can be an important resource of additional intensification of the dissolution of the Laves phase, because it can be accompanied by acceleration of the primary recrystallization and a change in the temperature range of the process [3].We studied the effect of the rate ofelectrocontact heating I in quenching on the phase composition and structural state of alloy 36NKhTYuM8 melted at a plant (0.04% C, 35.5% Ni, 13.5% Cr, 7.82% Mo, 2.93% Ti, 1.16% A1, the remainder Fe).We tested a 0.3-mm-thick ribbon after cold plastic deformation with a 50% reduction (as received). A detailed description of the method of research can be found in [2]. The volume fraction of the particles of the Laves phase in the structure of the alloy was deter...

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