[Show abstract][Hide abstract] ABSTRACT: The effect of alloying and fast-neutron irradiation on the behavior of interstitial impurities in vanadium and V-Ga and V-Ti-Cr
alloys is studied using low-frequency internal friction. It is found that, before irradiation, oxygen and nitrogen impurities
in plain vanadium and V-Ga alloys are in a solid solution, whereas, in V-Ti and V-Ti-Cr alloys, they are predominantly fixed
to form chemical compounds. Unlike the irradiation of plain vanadium, the irradiation of V-Ga alloys at 673 K to a neutron
fluence of 4.24 × 1025 m−2 (E > 0.1 MeV) does not knock out oxygen and nitrogen impurities from interstitial positions in the lattice to the positions
of radiation defects. In the V-5Ti-5Cr alloy, oxygen and nitrogen atoms are fixed before and after neutron irradiation according
to these conditions.
No preview · Article · May 2008 · Russian Metallurgy (Metally)
[Show abstract][Hide abstract] ABSTRACT: The effects of neutron irradiation and annealing on the elastic moduli and electrical resistivity of Mo and W were studied using single-crystal samples oriented with their axis along , , and . The samples were irradiated with fast neutrons (E> 0.1 MeV) to a neutron fluence of 1.14 1026n/m2in a BR-10 reactor at 460C. The irradiation-induced changes in resistivity and elastic moduli were found to be orientation-dependent. Irradiated W was found to exhibit elastic anisotropy and relaxation of the shear and Young's moduli. Isochronal annealing below 0.7t
mdid not reduce the resistivity of the samples to its initial level, presumably because of the formation of radionuclides, while the shear and Young's moduli were restored to their initial levels.
No preview · Article · Jul 2001 · Inorganic Materials
[Show abstract][Hide abstract] ABSTRACT: Vanadium and vanadium alloys with gallium, chromium and cerium were irradiated at 400°C in the BR-10 reactor. The neutron fluence was 5.15·1025 n/m2 (E>0.1 MeV). The elastic modules (E and G) and swelling of the alloys were measured after irradiation. It is established that swelling in the alloys is negligible and the elastic properties do not change significantly after irradiation. The experimental results are briefly discussed.
No preview · Article · Oct 1998 · Journal of Nuclear Materials
[Show abstract][Hide abstract] ABSTRACT: The temperature and chemical-composition dependences of the thermal conductivity, Young's and shear moduli, Poisson ratio, and internal friction of the V - 2-7 at. % Ga alloys additionally alloyed with 5 - 6 at. % Cr and 0.05 at. % Ce were studied. The thermal conductivity of all materials studied increases and Young's modulus and Poisson ratio decrease virtually linearly with increasing temperature. The thermal conductivity of the alloy decreases due to the alloying of vanadium with gallium and is virtually independent of the additions of chromium and cerium. Young's and shear moduli and Poisson ratio increase with gallium content and insignificantly change after additions of chromium and cerium.
[Show abstract][Hide abstract] ABSTRACT: The temperature dependencies of elastic modulus, internal friction, Poisson ratio in the range from 20 to 600°C as well as of thermal conductivity and electrical resistance at temperatures from 20 to 1000°C have been determined for type 13Cr2MoNbVB ferritic—martensitic steel irradiated at 280°C in the BN-350 fast reactor to neutron fluence of 4.03 × 1026 n/m2 (E > 0.1 MeV). During isochronal annealings at temperatures up to 0.65Tm the recovery of the properties for irradiated steel has been investigated in the range of homologous temperatures from 0.28Tm to 0.53Tm. A pronounce recovery was observed at four substages in the temperature interval from 380 to 620°C. The activation energies determined for all recovery substages varied from 1.11 eV to 4.09 eV.
No preview · Article · Oct 1996 · Journal of Nuclear Materials
[Show abstract][Hide abstract] ABSTRACT: Results of the experimental study of some physical, mechanical and technological properties of the reduced activation vanadium—gallium-based alloys are presented. The activation calculations show that Ga has the lowest cooling time not only in comparison with alloying elements Ti and Cr in low activation VTiCr alloys but also with vanadium. The effect of Ga(1–8 at%), Cr (5–6 at%) and Ce(0.05–0.1 at%) on workability, mechanical properties, thermal conductivity, elastic modulus (E,G), and Poisson's ratio of VGa was studied. The same properties of some are also studied. The level of tensile properties, thermal conductivity and elastic properties of VGa alloys are comparable with VTiCr alloys, but their activation parameters and ductility are superior. The experimental results make it possible to recommend VGa-based alloys as reduced activation structure materials for fusion reactors.
No preview · Article · Oct 1996 · Journal of Nuclear Materials
[Show abstract][Hide abstract] ABSTRACT: Temperature (20-600°C) and concentration dependences of shear and elastic moduli, Poisson's ratio and internal friction were investigated for vanadium, binary V-Ti (10-30 at.%) and ternary V-Ti (10-20 at.%)-Cr(6-10 at.%) alloys considered as candidate materials for fusion reactor first wall. A number of alloys was additionally doped with Si, Y and Zr. It is shown that a temperature increase promotes a linear decrease of elastic moduli for all alloys studied. Variations in titanium contents result in nonmonotonous change of elastic constants. Based on the results obtained the ternary vanadium alloys with 5-10 at.%Ti and 5-6 at.%Cr are considered to be optimal low activated thermonuclear reactor materials.
[Show abstract][Hide abstract] ABSTRACT: Ambient-temperature density. Young's and shear moduli, Poissons and expansion ratios, 20-940 C thermal conductivity of V-4Ti-4Cr and V-8Ti-5Cr alloys, promising structural materials for first walls of thermonuclear reactors, have been measured. Analytical temperature dependences of measured properties have been obtained. A comparison of physical and thermal properties of investigated alloys among them and with literary data for vanadium has been carried out. Annealed V-4Ti-4Cr alloy features the best combined properties as first-wall thermonuclear-reactor material.