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.

Review of the oxidation rate of zirconium alloys.

Abstract: The oxidation of zirconium alloys is one of the most studied processes in the nuclear industry. The purpose of this report is to provide in a concise form a review of the oxidation process of zirconium alloys in the moderate temperature regime. In the initial ''pre-transition'' phase, the surface oxide is dense and protective. After the oxide layer has grown to a thickness of 2 to 3 {micro}m's, the oxidation process enters the ''post-transition'' phase where the density of the layer decreases and becomes less protective. A compilation of relevant data suggests a single expression can be used to describe the post-transition oxidation rate of most zirconium alloys during exposure to oxygen, air, or water vapor. That expression is: Oxidation Rate = 13.9 g/(cm{sup 2}-s-atm{sup -1/6}) exp(-1.47 eV/kT) x P{sup 1/6} (atm{sup 1/6}).

Effects of alloying elements on deformation mode in Ti-V based β titanium alloy system

Abstract: We have discussed the rule by which the predominant cold deformation modes of metastable β phase are governed depending on their chemical compositions through the examinations of the effects of Sn, Al, and Zr on β-quenched and slightly cold rolled microstructures in a Ti-V based alloy system. It seems in Ti-V binary alloys, that orthorhombic martensitic transformation temperatures Ms and Md are depressed far below room temperature by the athermal ω phase at over about 15%V. Tin and aluminum intrinsically lower these temperatures like vanadium. On the other hand, tin and aluminum simultaneously suppress the athermal ω phase of Ti-16V to first rise Md and even Ms up to above room temperature, respectively. The deformation mode of β phase consequently depends on both the Md temperature and the degree of suppression of the athermal ω phase formation. Alloys having a Md above room temperature undergo stress-induced martensitic transformation. As for alloys having a Md below room temperature, alloys where the athermal ω phase is sufficiently suppressed undergo slip, whereas alloys where it is not so done {332} twinning. Since aluminum strongly suppresses the athermal ω formation, increased Al additions change the deformation mode of Ti-16V from {332} twinning to stress-induced martensitic transformation via a quenched α'' region or that of Ti-16V-4Sn from stree-induced martensitic transformation to slip. On the other hand, since tin does not suppress it so much as aluminum, increased Sn additions first change the deformation mode of Ti-16V from {332} twinning to stress-induced martensitic transformation but subsequently revive {332} twinning again before slip. The deformation mode of Ti-V-Al-Sn alloys can be interpreted by superposing the effects of V, Al, and Sn. Zirconium also depresses martensitic transformation temperatures and Ti-14V-6Zr undergoes stress-induced martensitic transformation. However, Ti-16V based Zr-added alloys undergo {332} twinning in the wide range of Zr content because the athermal ω phase formation is rarely suppressed by zirconium. This interpretation has solved the discrepancy of the transition of deformation modes of β titanium alloys.

Corrosion resistant zirconium alloys containing copper, nickel and iron

Abstract: Zirconium-based corrosion resistant alloys for use primarily as a cladding material for fuel rods in a boiling water nuclear reactor consist essentially of by weight percent about 0.5 to 2.0 percent thin, about 0.24 to 0.40 percent of a solute composed of copper, nickel and iron, wherein the copper is at least 0.05 percent, and the balance zirconium. Nuclear fuel elements for use in the core of a nuclear reactor have improved corrosion resistant cladding made from these zirconium alloys or composite claddings have a surface layer of the corrosion resistant zirconium alloys metallurgically bonded to the outside surface of a Zircaloy alloy tube. The claddings may contain an inner barrier layer of moderate purity zirconium metallurigcally bonded on the inside surface of the cladding to procide protection from fission products and gaseous impurities generated by the enclosed nuclear fuel.

EXAFS studies of the local order in amorphous and crystalline nickel-zirconium alloys. II. Structure of the amorphous alloys

Abstract: Amorphous NixZr1-x alloys with the nominal compositions x=0.241, 0.333 and 0.365 are investigated by means of extended X-ray absorption fine structure (EXAFS). Spectra were taken at both the Ni and the Zr K-absorption edges. Significant differences show up in the nearest-neighbour environment of the amorphous alloys compared with the crystalline state. The amorphous compound with x=0.333 is compared with the corresponding crystalline phase with well known CuAl2 (C16)-type structure. The Ni-Zr bond length in this amorphous alloy is 0.14 AA shorter than in the crystalline state. The small widths of the Ni-Zr atomic pair distributions in the amorphous alloys indicate a significant short-range order. A comparison of the amorphous alloys investigated shows no significant change in the environment of Ni with changing composition whereas in the Zr environment an increase of the Ni coordination number is observed with increasing Ni content.