Radiation-Induced Phase Transformations in Zirconium Alloys under Long-Term Irradiation

Variation of the phase composition and structure of zirconium alloys É125 and É635 under the action of irradiation is studied by the methods of microscopic x-ray energy dispersion analysis, radiographic analysis, and analytical transmission electron microscopy. Special features of phase transformations in the alloys under the action of long-term neutron irradiation at 290 – 315°C are analyzed.     

Zirconium alloys in nuclear power engineering

Results of studies of zirconium alloys É110 and É635 that have served in parts of VVÉR-1000 reactors are presented. The influence of the composition on the properties of alloys É110 and É635 is studied and improved modifications are suggested. The effect of the total content of admixtures in alloy É110 on corrosion and embrittlement of pipes under conditions simulating LOCA is investigated.     

Classification and Characteristics of Materials for Metallic Seals

Criteria for choosing steels, alloys, and coatings for elastic metallic seals of detachable joints (DJ) of high-power liquid-propellant engines (LPE) are considered. The correctness of the choice of materials and coatings made in accordance with the developed criteria has been confirmed by reliable operation of LPE employed in advanced Énergiya, Zenit, and Atlas rocket carriers and the Énergiya-Buran space rocket system.     

Structure and properties of deformable nickel alloys for gas turbines

The construction of high power gas turbine installations necessitates the development and use of new high-strength heat-resistant nickel alloys for large forged turbine blades. The blade material must possess not only superior properties (high temperature strength, ductility, fatigue and thermal fatigue strength, stability in the fuel combustion products) but also the required level of metallurgical and manufacturing producibility. The results of a study of the deformable nickel alloys KhN65KVMYuTB (ÉK78), KhN65KMVYuB (ÉP800), and KhN60KVYuMB (ÉP957), which have substantially better properties than the alloy now used for gas turbine blades (KhN65VMTYu) (ÉI893), are presented in this article.Scientific-Production Organization TsNIlTMASh. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 16–20, December, 1994.     

Treatment of metals in liquid nitrogen with subsequent “rest” at room temperature

Cold treatment is used for decreasing the amount of retained austenite in hardened steel. Cooling to low temperatures can also be effective for alloys that do not undergo a martensite transformation, for example, alloys based on aluminum and nickel. The article concerns special features of treatment of alloys of grades AMtsM, ADIM, and NP-2É in liquid nitrogen.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 26–28, March, 1996.     

Classification of the structure of titanium α and pseudo-α casting alloys

The structure and properties of titanium casting alloys VT5L, VT20L, and VT21L with various impurity contents are studied. A classification is developed for the cast structure of these alloys. The change in the cast structure under constant cooling is shown to depend on the impurities as well as on the concentration of alloying elements. An interrelation is established among the structure of alloys, the fracture topography, and the mechanical properties.K. É. Tsiolkovskii Aviation Technology Institute, Moscow. Rybinski Aviation Technical Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 28–30, March, 1994.     

Heat-resisting Kh25N12Ar steel

Conclusions Steel Kh25N12AR (ÉP618), with high mechanical, heat-resisting, and thermal stability characteristics, can be used as a substitute for a series of steels and alloys with high nickel concentrations, such as ÉI417, ÉI435, etc.Electrostal' Plant. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 32–34, February, 1968.     

Softening mechanism in high-temperature nickel alloys subjected to thermomechanical treatment in long-term high-temperature tests

It is known that in high-temperature tests the rate. of softening in nickel alloys after termomechanical treatment (TMT) is higher than after the standard heat treatment (SHT). For low-alloyed alloys of the ÉI437B type this is associated with the development of recrystallization at operating temperatures of 650 – 750°C. Complexly alloyed high-temperature nickel alloys are characterized by a higher content of the y'-phase, a wide range of the double-phase (+ )-state, and, as a consequence, a considerably higher recrystallization temperature compared to alloy ÉI43B7. However, these alloys often lose strength after TMT more intensely than after SHT. The causes of this phenomenon have not been determined so far. This investigation is devoted to the solution of this problem.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 19–21, September, 1995.     

High-temperature ductility of nickel alloys type KhN55MBYu with a high iron content

In order to prepare stamped and welded structures which operate in the temperature range from 750 to –253°C there is use of high-strength dispersion-hardening nickel alloys KhN55MBYu (ÉP666) and KhN58MBYuD (ÉK61) which exhibit resistance to hot crack formation during welding and cracking of welded joints during defonnation. Alloys of this type have a high level of strength (_f = 1300 N/mm² at 20°C) and toughness at cryogenic temperatures, and they have high resistance to plastic deformation in the temperature range for hot pressing especially in the cast condition. In order to find the optimum forging and stamping schedules for these alloys features of the change in their structure and properties in relation to the forming temperature have been studied.I. P. Bardin Scientific Research Institute of Ferrous Metallurgy, Moscow. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 25–28, September, 1994.     

Influence of deformation rate on the plasticity of certain steels and alloys

Conclusions The variation of the technological plasticity of the metals tested with an increase of the rate of cold upsetting from 0.001 to 25–100 m/sec is explained by the difference in the degree of heterogeneity of the structure formed. The reason for the impaired plasticity of alloys with an austenitic structure is the pronounced heterogeneity of the deformation structure.The improved plasticity of aluminum-base alloys (AK6, AK8, AV) is due to the greater uniformity of the deformation structure.In steel 45 and 40KhNMA the localization and irregularity of deformation increase to the same extent at all deformation rates tested.ÉNIKMASh. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 30–33, June, 1967.     

Investigation of the properties of vacuum and open melts of the KhN70VMTYu and KhN70MVTYuB alloys

Conclusions Vacuum induction smelting of the KhN70VMTYu alloy and vacuum are smelting of the KhN70MVTYuB alloy produces a higher impact strength at temperatures of hot plastic deformation and higher specific elongation and reduction in section at operating temperatures than ordinary are smelting. The increased plasticity of the vacuum melts of both alloys results from the reduction of the concentration of hydrogen and oxygen.TsNIIChERMET; Élektrostal'. Plant Translted from Metallovedenie i Termicheskaya Obrabotka Metallov, No.1, pp.25–28, January, 1967.     

A Theoretical Study of the Kinetics of Hydride Cracking in Zirconium Alloys

A diffusion model is suggested for computing the rate of delayed hydride cracking (DHC) in nonirradiated zirconium-base alloys. The rates of DHC in claddings of fuel elements of VVÉR and RBMK reactors and in pressure pipes of CANDU reactors are predicted.     

Corrosion resistance of chromium-coated 20895 electrical steel

Conclusions Chromizing electrical steel with the circulation technique over the range 950–1000°C improves the corrosion resistance in a wide range of oxidizing-reducing media and also in atmospheric conditions. In these circumstances, the coercive force is reduced, which is particularly important for magnetically soft alloys.L. Ya. Karpova Physicochemical Institute. N. É. Bauman State Technical University, Moscow. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 4–6, November, 1991.     

Study of Nb-N alloys after quenching and aging

Conclusion Maximum strengthening for alloys of the Nb-N system is observed after quenching from 1600°C and subsequent aging at 1300°C, which is due to formation of highly dispersed precipitates of stable NbN nitride phase uniformly distributed in the matrix. Generation of nitride phase particles during aging is accompanied by occurrence of elastic fields due to distortion of the crystal lattice of the matrix.N. É. Bauman MGTU. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 15–19, July, 1990.     

Structural Changes in Granulated Refractory Nickel Alloy ÉP741NP Under the Action of Hydrogen

Results of metallographic, electron microscopic, phase, and x-ray diffraction studies of the structure of alloy ÉP741NP tested in hydrogen at a pressure of 45 MPa and a temperature of 20, 460, 700, and 830°C are presented. It is shown that the hardening -phase grows in the alloys in the entire range of 20 – 830°C and its morphology changes under the action of hydrogen. The parameter of the crystal lattice increases too.     

Properties of aluminum alloys with a titanium nitride coating

The creation of a titanium nitride coating on the surface of articles is one of the most effective methods of enhancing the wear resistance of materials. This coating is also promising from the standpoint of the possibility of achieving high hardness, strength, and simultaneously good protective-and-decorative surface properties. We investigated the possibility of improving the tribotechnical characteristics and corrosion resistance of the widely known aluminum alloys PV-90, D16, and 1420 using the titanium nitride coatings applied by the ionplasma method.N. É. Bauman Moscow State Technical University. All-Union Scientific-Research Institute of Aviation Materials. L. Ya. Karpov Scientific Institute of Physical Chemistry. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 20–23, June, 1994.     

Field and accelerated tests of contact and volatile inhibitors of atmospheric corrosion with various metals

The results of two-year field (in rural, urban, and marine atmospheres) and accelerated tests of contact and volatile inhibitors with steel, brass, and aluminum and magnesium alloys are reported. The protective values of contact inhibitors (IPKhAN-29a and IPKhAN-50) were found to decrease by 30 to 60% in all of the aforementioned atmospheres in already one year of the tests. In sealed polyethylene bags, metals and alloys retained high corrosion resistance both without and with volatile inhibitors, regardless of the inhibitor’s nature IPKhAN-110 and DAN). The protective value of contact inhibitors only slightly depends on the atmospheric corrosivity, though the latter increased from rural to marine according to the ratio 1∶1.4∶5.7. For the inhibited systems, the results of the field and accelerated tests were shown to correlate.     

Superplastic-like behavior of Al-high Si alloys produced from rapidly solidified powders and ribbons

The high temperature tensile properties of hyper-eutectic Al-Si alloys were studied at temperatures between 683 and 813 K at initial strain rates between 8.3X10⁻⁴ and 4.2X10⁻¹s⁻¹. The alloys were prepared from prealloyed powders and ribbons, which were respectively fabricated by the centrifugal atomization and melt spinning, through the hot extrusion process at an extrusion ratio of 110:1. The extruded alloy bars prepared from the powders and ribbons, i.e. the powder-extruded and ribbon-extruded bars, have homogenous micro-structures with the fine silicon particles dispersed in the aluminum matrices for the Al-25Si and Al-15Si alloys. The maximum elongation-to-failure of the powder-extruded bar and the ribbon-bar are almost equal, 150%, for the Al-25Si alloy, In the Al-15Si alloy, the ribbon-extruded bar has superior elongation compared to the powder-extruded bar, that is, these are respectively 520% and 400%. The maximum elongation was attained at the relatively high strain rate of 10⁻²s⁻¹ independent of the silicon content and solidification process.     

Grain refinement and mechanism of CAl_（0.5）W_（0.5） compound in Mg-Al alloys

The effect of CAl0.5W0.5(CAW) compound on the grain refinement of Mg-Al based alloys was investigated.The results show that CAW compound is an effective and active grain refiner.The grain size of binary Mg-Al alloys is more than 500 μm,and it is changed to about 110 μm with a 1 wt.% CAW addition.The hardness increased with the decease of grain size monotonously.The mechanical properties are improved by the addition.The fine grain size is mainly ascribed to the dispersed Al2CO particles,which are very potent nucleating substrates for Mg-Al alloys.The nucleation cores formed by chemical reaction directly are well-distributed in the matrix.     

Phases precipitated in grain boundaries during slow cooling of maraging steels

Conclusions Maraging steels ÉP678, ÉP679, and ÉP699 cooled slowly from 1250° show precipitates of various phases in the grain boundaries, mainly titanium carbonitrides, the size and quantity of which increase with cooling. With cooling to 950–850° there are also particles that consist of titanium with oxygen, nitrogen, and carbon. These particles in the grain boundaries can cause embrittlement of the steels.Dnepropetrovsk State University. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 45–47, October, 1974.