Zirconium alloy

About: Zirconium alloy is a research topic. Over the lifetime, 6548 publications have been published within this topic receiving 78954 citations. The topic is also known as: zircaloy.

Developing a superplastic forming capability in a commercial aluminum alloy without scandium or zirconium additions

Abstract: Tests were undertaken to determine the feasibility of producing a superplastic forming capability in a commercial Al-2024 alloy through processing by equal-channel angular pressing (ECAP), where this alloy was selected because it contains no scandium or zirconium additions that are generally beneficial in retaining an array of small grains. Processing by ECAP produced grain sizes in the range from ∼0.3 to ∼0.5 μm and static annealing showed these ultrafine grains were reasonably stable at temperatures up to ∼700 K. Superplastic elongations were achieved after ECAP with a maximum elongation of ∼500% at 673 K when using a strain rate of 1.0×10−2 s−1. The strain rate sensitivity was measured as ∼0.3 suggesting that dislocation glide is the rate-controlling mechanism. These results demonstrate the potential for achieving high tensile ductilities in conventional commercial aluminum alloys through processing by ECAP.

Recent progress in corrosion-resistant metastable alloys

Abstract: Tailoring new corrosion-resistant alloys has recently been performed mostly by the sputter deposition technique. This technique is suitable for forming a single-phase solid solution even when the boiling point of one component is lower than the melting points of the other components and/or when one component is immiscible with another component in the liquid state. Aluminium-refractory metal, chromium-valve metal and molybdenum-chromium-nickel alloys have been successfully prepared in a single amorphous phase. Amorphous aluminium-refractory metal alloys are corrosion resistant in 1 M HCl and chromium-valve metal alloys are spontaneously passive in 12 M HCl, showing a better corrosion resistance in comparison with the alloy components. The amorphous aluminium-refractory metal alloys also have an extraordinarily high hot corrosion resistance. Their sulphidation resistance at higher temperatures is far higher than any other known metallic materials and their oxidation resistance is comparable to chromia- or alumina-forming alloys.

Oxidation of Zirconium Alloys in Oxygen at High Temperatures up to 1600 °C

Abstract: The oxidation kinetics of the classic pressurized water reactors (PWR) cladding alloy Zircaloy-4 has been extensively investigated over a wide temperature range. In recent years, new cladding alloys optimized for longer operation and higher burn-up are being increasingly used in Western light water reactors (LWR). These alloys were naturally optimized regarding their corrosion behavior for operational conditions. The publicly available data on high temperature oxidation of the various cladding materials are very scarce. This paper presents the results of a first test series with Zircaloy-4 as reference material, Framatome Duplex cladding, Framatome M5® and the Russian E110 alloy. The first two are Zr–Sn, the latter two Zr–Nb alloys. All materials were investigated in isothermal and transient tests in a thermal balance under argon–oxygen atmosphere. Strong and varying differences (up to 500%) of oxidation kinetics between the alloys were found till 1000 °C, where the breakaway effect plays a role. Smaller but still significant differences (20–30%) were observed at higher temperatures. Generally, the advanced cladding alloys here studied show also a favorable behavior at high temperatures during accident scenarios.

The Influence of Structure on the Corrosion of Glassy Copper-Zirconium Alloys

Abstract: Differences in structure between crystalline and glassy copper-zirconium alloys lead to subtle increases in the corrosion rate of crystalline compared to glassy material. Glassy alloys of Cu60Zr40 were melt spun and subsequently devitrified, yielding single phase polycrystalline material. Comparing the potentiodynamic polarization response of these structural types revealed no significant difference in ϕcorr. ba, bc, icorr. and io. Other alloys, Cu58Zr42 and Cu55Zr45, compared in glassy and crystal-line forms revealed that inhomogeneity, caused by precipitation of a second phase, did not alter the corrosion behavior from that of single phase Cu60Zr40. Corroded glassy surfaces were generally smooth except for scattered hemispherical features, while crystalline surfaces were densely populated with these features. Corrosion of copper-zirconium alloy occurs by the selective dissolution of zirconium in the vicinity of ϕcorr, whereas, at potentials noble to −0.1 VSCE, copper contributes to the anodic c...