Irradiation of metals and alloys with neutrons, electrons, heavy ions, or γ-rays may introduce up to 108 J/mol of energy in the form of atomic displacements. This energy, which is in the form of vacancies, self-interstitials, and cores of displacement cascades is then available to produce a range of phase changes and microstructural alterations which are not observed under thermal conditions. There exist numerous mechanisms to convert part of this displacement energy into microstructural change, including irradiation-induced solute segregation, Frenkel pair recombination at the particle: matrix interface, irradiation disordering or amorphization, and recoil resolution of atoms from precipitates. In addition, the cores of displacement cascades may act as precipitate nucleation sites and Frenkel pair recombination may trigger spinodal-like instabilities. The theory of these mechanisms is developed in some detail, and is followed by a systematic review of experimentals observations of irradiation-altered phase stability. The observations include enhanced nucleation on displacement cascades, precipitation induced by solute segregation to defect sinks, nucleation of wrong phases, disordering and amorphization, Frenkel pair recombination driven precipitate, and inverse Ostwald ripening.

Phase Stability Under Irradiation

I have tried to summarize the oxidation behavior of zirconium and its alloys in both gaseous and aqueous environments, and to show how other environments, such as liquid metals, can be considered as special cases of one or other of the main classes. It will be appreciated from the extent of the literature on zirconium alloys (the over-600 references are by no means a complete bibliography) that it was impossible to discuss the details of many of the studies reported. To achieve a comprehensive survey in the space available it has been necessary to present a single coherent view of the field, without perhaps devoting sufficient space to opposing views and the evidence adduced in their favor. I have endeavored to make the references as comprehensive as possible, however, only omitting some early ones that are cited in later publications, which adequately summarized their contents. Readers who may be stimulated to pursue the details of any particular aspect of the field should have little difficulty tracing these other references from the bibliographies of the works that are cited. Finally, if the gaps in our knowledge, which I have attempted to illuminate, provide the inspiration for even one reader to devise experiments which can unambiguously resolve some of the many still unanswered questions, then I will consider this review to have been worthwhile.

Oxidation of Zirconium and its Alloys

Effect of composition and heat treatment on the microstructure and corrosion behavior of ZrNb alloys

Zirconium—an international nuclear material

Oxidation of β-Zr and related phases in Zr–Nb alloys: an electron microscopy investigation

In the absence of radiation the corrosion of quenched, cold worked and aged Zr-2.5 Wt% Nb in 280 C (536 F) pressurized water decreases with increasing aging time and temperature. Under neu...

A. B. Johnson

Papers

Effect of Aging and Irradiation on the Corrosion of Zr-2.5 Wt% Nb