[en] Highlights: • The ω phase improves super-elasticity of 75%-rolled Ti–24 at.% Nb–2 at.% Zr alloy. • The ω phase inhibits stress-induced martensitic transformation in 95%-rolled Ti–24 at.% Nb–2 at.% Zr alloy. • The ω phase promotes pitting, and decreases corrosion resistant of the alloy. A recently investigated Ti–24 at.% Nb–2 at.% Zr alloy was cold-rolled with reductions of 75% and 95%, and the resulting materials were heat-treated under the same conditions. The two types of specimens obtained through this procedure show the same phase composition. Precipitation of an isothermal ω phase leads to some improvement in the properties of the 75%-rolled specimens. The 95%-rolled and subsequently heated specimens exhibit different performances compared to the 75%-rolled samples heated under the same processing conditions. The stress-induced martensitic transformation is inhibited in the 95%-rolled specimens, owing to the combined effects of the isothermal ω phase and texture. The Ti–24 at.% Nb–2 at.% Zr alloy shows open circuit potential and corrosion behavior similar to commercially pure Ti. The corrosion resistance of the alloy is reduced upon precipitation of the ω phase, owing to an unstable passive film.

[en] The potentiodynamic polarization studies were carried out on Zr based bulk amorphous alloy Zr₅₇Cu_15.4Ni_12.6Al₁₀Nb₅ and Zr₅₉Cu₂₀Ni₈Al₁₀Ti₃ in solutions of 1 M, 6 M and 11.5 M HNO₃ aqueous media at room temperature. As received specimens of Zr₅₇Cu_15.4Ni_12.6Al₁₀Nb₅ (5 mm diameter rod) and Zr₅₉Cu₂₀Ni₈Al₁₀Ti₃ (3 mm diameter rod) were polished with SiC paper before testing them for potentiodynamic polarization studies. The amorphous nature of the specimens was checked by X-ray diffraction. The bulk amorphous alloy Zr₅₉Cu₂₀Ni₈Al₁₀Ti₃ shows the better corrosion resistance than Zr₅₇Cu_15.4Ni_12.6Al₁₀Nb₅ alloy in the aqueous HNO₃ media as the value of the corrosion current density (I_corr) for Zr₅₇Cu_15.4Ni_12.6Al₁₀Nb₅ alloy were found to be more than Zr₅₉Cu₂₀Ni₈Al₁₀Ti₃ alloy in aqueous HNO₃ media. The improved corrosion resistance of Zr₅₉Cu₂₀Ni₈Al₁₀Ti₃ alloy is possibly due to the presence of Ti and formation of TiO₂ during anodic oxidation. Both Zr based bulk amorphous alloys shows wider passive range at lower concentration of nitric acid and the passive region gets narrowed down with the increase in concentration. A comparison of data obtained from both the Zr-based bulk amorphous alloys is made and results are discussed in the paper. (author)

[en] There are two possible approaches to applying ion implantation to the modification of the corrosion behavior of metals and alloys. The first approach is to use ion implantation to produce metastable or amorphous corrosion-resistant surface alloys. Secondly, ion implantation can be used to introduce controlled amounts of various elements into the surface of a metal

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[en] Described is a method of determination of corrosion cracking (CC) resistance characteristics for metals applied for industrial machines and plants. The method is based on CC consideration as a kinetic process described by the degree equation and on the application of the lg delta-lg tau diagram as characteristics to CC material, a yield strength deltasub(CC10sup(5)) and a ratio of deltasub(CC10sup(5)) value to yield strength and ultimate strength

[en] The goal of this study was to determine the corrosion resistance of NiCrA1Y coatings for use in future supercritical water reactors (SCWR). The NiCrA1Y coating was applied to IN625 and was tested against bare IN625, under stress, in high density supercritical water (HDSCW) and low density supercritical water (LDSCW). The IN625 samples experienced intergranular corrosion in HDSCW but not in LDSCW as well as oxidation; whereas the NiCrA1Y sample experienced oxidation, with no other forms of corrosion observed. Thus, it is likely that NiCrA1Y coatings are more corrosion resistant than IN625 in HDSCW. (author)

[en] Applications limited to metallic materials are considered in three areas: hot working tools, furnace parts and electric heating elements. In the case of hot working the most important factor is high temperature mechanical strength, whereas oxidation/corrosion resistance is the major prerequisite for electric heating elements and a combination of both is essential for furnace parts, with efforts to improve the price/service life ratio

[en] The object of this invention is to reduce the weight and improve the neutron absorbing performance and corrosion resistance of a nuclear reactor control rod to a sufficiently practical level. The control rod comprises an alloy containing, on the weight base, at least one of 0.1 to 5% Fe, 0.1 to 5% Ni, 0.1 to 3% Cr, 0.1 to 2% Nb and 0.1 to 2% Mo, 5 to 50% Hf and the substantial balance of Zr. Further, at least one of 0.1 to 3% Sn and 0.05 to 1% Si may be incorporated into the alloy. As a result of the experiment using the alloy according to this invention and B₄C powder together, it has been found that they have excellent property both in the neutron absorbance and corrosion resistance. It has also been found, as the result of the experiment not using B₄C together, that they have excellent corrosion resistance and stable property for a long period of time although the neutron absorbance is somewhat reduced. Accordingly, it is possible to reduce the weight of the control rod while keeping practically sufficient neutron absorbance and excellent corrosion resistance. (I.S.)

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