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A polymorphic transformation between BCC and FCC phases can be described in the framework of the root lattice E8in a 8D-space as the hypothetical praphase with symmetry group playing a role of the supergroup for both participants of the transformation. The special subset of vectors of the E8and coinciding topologically with the unit cell of the A15 structure (Cr3Si-type) in the 3D Euclidian space was found, this subset can be regarded as an intermediate configuration during transformation between FCC and BCC structures. The proposed description of the polymorphic transformation is supported by experimentally observed habite planes of martensite in iron based alloys and by the existence ofthe A15-phase in the solid oxygen.

1.The plasma heating process of 9KhF steel provides obtaining of hardened surface cases with a martensitic structure. The depth of the hardened cases with a microhardness of more than 800 H may reach 1 mm.2.The depth of the hardened case changes proportionally to the parameter P/(dnP)0.4, where P is the arc power, dn is the diameter of the plasmatron delivery nozzle, and v is the rate of movement of the plasmatron.3.The thermal efficiency of the plasma-hardening process of 9KhF steel is 25–30% with the use of argon as the plasma-forming gas. With operation of the gun with a mixture of Ar+70% N2 the thermal efficiency decreases to 9–10%.

1.The quantity of residual austenite in the case fused under the action of a heat source (laser or plasma) on the surface of steel or iron is unambiguously determined by the parameter P/d (dv)0.4, which is proportional to the maximum temperature at the end of action of the source.2.In 9Kh steel with an increase in the parameter P/d (dv)0.4 the quantity of residual austenite in laser fusion changes according to a curve with a maximum. In treatment with scanning of the laser beam the quantity of residual austenite in 9Kh steel continusouly increases with an increase in the parameter P/d (dv)0.4. The addition of scanning leads to an increase in the quantity of residual austenite in the case in comparison with treatment without scanning.3.With an increase in the parameter P/d (dv)0.4 the change in the quantity of residual austenite in the zone of surface fusion of gray irons is dependent upon the degree of solution of graphite in the molten material.4.The contact fatigue life of 9Kh steel after laser fusion of the surface is a maximum with 50–60% residual austenite in the laser hardened case. The wear resistance of gray iron after surface fusion increases with an increase in the quantity of residual asustenite in the case hardened from the liquid state.

The fifth issue of the journalEnergy Economics, Technology, Ecology in 1994 has published an article entitled “Some Problems of the Iron Century of Russia,” which is an unprejudiced, free, bee, and compact review of the modern saw of metallurgy in the country. Metal science and the metal industry are directly concerned with the state of affairs in metallurgy, and therefore we believe that the article will be interesting for our readers. With the authors' consent, we present the article with some additional facts and examples added by the authors at the request of the editorial board in order to a] low for the specific interests of our readers. We believe that the information reported by the authors is interesting and instructive, but we have neither the right nor the opportunity to make any conclusions.

Experiments on the quenching of cast iron from the liquid state were carried out by A. Ulitovskii as early as the 1930's. Intensive studies of the structure of quenched melts which were carried out in the early 1960's revealed several new structural states in metallic systems: supersaturated solid solutions, new metastable intermediate phases (not typical of the given system at equilibrium), metallic glasses (amorphous phases), and quasicrystalline phases. In order to explain these effects (not including new phases) special theoretical models are usually proposed, which are at times yen elaborate. Based on the published data it is possible to describe these structural states from a unified point of view excluding the concept of diffitsionless solidification.

The martensitic transformation is a special form of phase transformation that is not associated with the conventional temperature-dependent parameters: the number of centers and the crystal growth rate. The internal stresses are important for this transformation. How can we define the martensitic transformation? Possibly as follows: “The martensitic transformation is a diffusionless phase transformation that is induced by the stresses.” The stream of studies devoted to the martensitic transformation is not abating, and each author often has his own point of view. But they all contribute very little to clarification of the nature of this phenomenon and, unfortunately, even less to their use in practice; for example, for regulation of the kinetics of the transformation. We shall present two articles that are devoted to the profound causes and subtle characteristics of the martensitic transformation.

After melting the thin surface layer of steels and pig irons with a localized heat source, the amount of residual austenite in this layer is determined by the degree of dissolution of the carbide phase and correlated with the maximum temperature attained at the end of the heating stage. In this work, we have investigated the effect of the amount of residual austenite in the melted layer on the wear resistance, the contact fatigue, and the anodic dissolution from some steels and pig irons.

1.In fusion of the surface of gray iron by a laser beam with scanning the thickness of the fused layer with a constant scanning frequency is proportional to the parameter P/(dv)0.4, where P, d, and v are the power, diameter, and rate of linear movement of the laser beam, respectively. This relationship was obtained in solution of the threedimensional problem of laser heating.2.The zone of laser fusion of the iron has a dispersed dendritic structure and the phase composition is an a+?+Fe3C mixture. With a change in rate of movement of the specimen (v) from 1.7 to 10 mm/sec the quantity of the phases in the remelted layer remains practically constant. With scanning the quantity of the phases does not change in comparison with treatment without scanning. With an increase in rate the carbon content in the austenite increases from 1.2 to 1.5%. The microhardness of the zone of fusion does not depend upon v and is 900–1000 H.

1.The increase in the microhardness of commercial iron containing 0.035% of C as a result of rapid remelting of the surface layer by laser irradiation is governed by the ??a transformation in accordance with the martensitic shear mechanism.2.The martensite forming as a result of laser treatment exhibits a stacked morphology with a transverse stack dimension of 0.4–0.6 µm.

Recently created pulsed gas lasers with high pulse repetition rate produce radiation in the IR [ V. Yu. Baranov , in Molecular Gas Lasers. Physics Applications, VelikhovE. P., Ed. ( Mir, Moscow, 1981), pp. 252– 255] and the UV ( V. Yu. Baranov , in Proceedings, International Conference on Lasers, 14–18 Dec. 1981, pp. 968– 974) regions of the spectrum. These lasers are widely used in research on the selective excitation of matter. This field of study includes laser isotope separation { G. I. Abdushelashvili , Kvantovaya Elektron. (Moscow)9, 743 ( 1982) [ Sov. J. Quantum Electron.12, 459 ( 1982)]} and laser-induced chemical reactions [ V. Yu. Baranov , Preprint IAE 3693/13 ( Moscow, 1982)]. But there are few publications dealing with uses of high-repetition-rate lasers for materials processing, although this problem undoubtedly is of considerable scientific interest.

1.The applicability of the unidimensional model of heating a homogeneous semi infinite body for selecting the parameters of laser hardening without fusion of the surface of carbon steels with different carbon content was experimentally confirmed.2.Upon transition from the regime of heating with fusion of the surface to the regime of heating without fusion, the shape of the laser track changes.3.The distribution of microhardness across the thickness of the zone of laser hardening is not the same in steels with different carbon content: with 0.2% C the microhardness of steel decreases monotonically, with 0.8% C it decreases stepwise. Such a change of the microhardness profile upon change of carbon content may be connected with the different path length of carbon diffusion in steels with different amounts of hypoeutectic ferrite.

Conclusions 1.An investigation was carried out into the pressing of powders of the brittle intermetallic compound SmCo5 in a magnetic field and into the desnfication of SmCo5 powder magnets by cold working under conditions of high hydrostatic pressures.2.A device has been constructed for pressing powders in a magnetic field by the application of high fluid pressure, in which the movement of powder in the direction of the orienting magnetic field is restricted.3.In the pressing of SmCo5 powders in a magnetic field with restricted powder displacement in the direction of the field, the degree of particle orientation (degree of magnetic texture) in the resultant magnets grows linearly with increase in the strength of the orienting field. A degree of texture close to unity is attained in fields of about 15 kOe.4.Cold working with a reduction of 15–20% under conditions of high hydrostatic pressure enables the density of SmCo5 powder magnets to be increase to 90–94% of theoretical.

For the 40th anniversary of our journal the Editor-in-Chief A. P. Gulyaev asked each member of the editorial board to write a brief article with a retrospective. In the article we were to describe the most interesting events that have occurred in the field of metals science and heat treatment during the 40 years of the existence of the journal and our contribution to the development of this science.