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doi: 10.1007/BF00712244pmid: N/A
1. Introduction of aluminum into Fe-Mn alloys causes a marked increase in the amount of γ and α phases with a reduction in the ε-martensite content. Silicon under these conditions promotes stabilization of ε and α phases with a reduction in the amount of austenite. 2. With deformation of Fe-Mn-Al alloys there is marked austenite destabilization, and in Fe-Mn-Si alloys an increase in the amount of α and γ phases is observed due to a reduction in the amount of ε-martensite. 3. The effect of aluminum and silicon on the stability of phases when they are simultaneously added to Fe-Mn alloys is not additive.
doi: 10.1007/BF00712245pmid: N/A
1. The content of alloying element in α-solid solution based on aluminum with increasing melt cooling rate during crystallization changes by a curve with a minimum, but the amount of intermetallic phases changes by a curve with a maximum. 2. The cooling rate with which the minimum concentration of alloying elements in solid solution is obtained, its equilibrium concentration, and also complete solubility, depend on the nature of alloying element and its concentration in the alloy. 3. The dependence of alloying element concentration in α-solid solution on its content in the alloy in the case of actual crystallization differs from this dependence obtained from the phase diagram by the fact that alloying element concentration in nonequilibrium alloys with which the maximum concentration Cα is obtained exceeds the limit of total solubility.
doi: 10.1007/BF00712246pmid: N/A
1. Isothermal aging of beryllium bronze BrB2 at 260–400°C is accompanied by structural transformations connected with decomposition of supersaturated α-solid solution. 2. Formation of γ′-phase nuclei (or regeneration of GP zones) and also their growth proceeds at the expense of cooperative-displacement processes characterized by low activation energy (19.7–26.3 J/mole) and significant relaxation time (τ⋟10−1−102 sec).
Bernshtein, M.; Odesskii, P.; Grunvald, T.
doi: 10.1007/BF00712248pmid: N/A
1. Steel 15G2SF treated by a TMT method consisting of preliminary austenitization at temperatures above $$A_{C_3 }$$ , followed by cooling to the temperature of the middle of the intercritical temperature range, than by 50% deformation, and by water cooling and high-temperature tempering at 620–650°C, acquires high tensile strength (σy ≥ 600 MPa, σu ≥ 700 MPa) and ductility, together with unusually high impact toughness at subzero temperatures (a 0.25 −70 ≥2.0 MJ/m2,a t −70 ≥1.0 MJ/m2. 2. The treatment studied has some economic and technological advantages in comparison with controlled rolling at temperatures below $$A_{r_3 }$$ . For instance, the optimum results can be achieved using cheap, Nb-free steel 15G2SF. The high-temperature tempering makes precise control of the treatment in the intercritical temperature range unnecessary.
Gulyaev, A.; Konoval'tsev, V.; Nikitin, V.
doi: 10.1007/BF00712250pmid: N/A
1. In the nitriding process the steel is not monotonically saturated with nitrogen. The period during which the thickness of the nitride zone increases alternates with the latent period, in which the thickness of the layer remains practically unchanged. These periods coincide in time with the periods of increasing and decreasing hardness encountered during diffusion saturation. 2. During saturation, a solid solution supersaturated with nitrogen forms; a certain attendant increase in hardness is the result of solid-solution hardening and increase of the thickness of the nitride zone; however, the basic increase in hardness of the layer is attained during cooling in consequence of dispersion hardening of the α-phase.
Kogan, Ya.; Shashkov, D.; Likhacheva, T.
doi: 10.1007/BF00712251pmid: N/A
1. Nitriding leads to the formation of a nitride zone and a zone of internal nitriding on the surface of niobium alloys; the thickness of these zones increases with rising temperature and with increasing saturation time, and it changes extremally in dependence on the preliminary plastic deformation in rolling. The zone of internal nitriding is thickest in specimens subjected to a degree of deformation up to 50%; the thickness of the nitride zone is then minimal. The formation of a more developed sublayer ensures greater hardness at greater depth. 2. Nitriding of niobium alloys in the recrystallized state leads to better strength properties and lower ductile properties. Nitriding of niobium alloys in the deformed state leads to a noticeable decrease of strength, apparently because of strong embrittlement. With the degree of deformation increasing to 50%, the strength of niobium alloys after nitriding increases, and when the degree of deformation increases further to 75 and 90%, it decreases. 3. Niobium alloys deformed before nitriding to a low degree (up to 50%) have the highest creep limit and the lowest wear resistance.
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