[en] After a review of computer-simulation results and of experiments on intrinsic point defects in hexagonal close-packed metals a comprehensive analysis of the available data is presented. Particular emphasis is put on the detailed interpretation of the observations on X-ray Huang scattering after electron irradiation, on lattice-parameter changes induced by fast-neutron irradiation, on perturbed angular γ-γ correlation in Zn and Cd, on positron annihilation in Zr and Ti, and on self-diffusion in Zr. The main conclusions are that in most hcp metals two distinct self-interstitial configurations exist, which undergo long-range migration in the recovery stages I_E and III, that mono-vacancy migration takes place in recovery stage IV, and that self-diffusion occurs predominantly via a vacancy mechanism. In a brief discussion of irradiation growth in Zr and its alloys the technological importance of a comprehensive knowledge on intrinsic point defects and their agglomerates is demonstrated. (orig.)

[en] The present review of defects in α-Zr is concerned with atomic and vacancy diffusion and with solute effects on radiation damage. The primary aim, in addressing atomic diffusion, is to try to expose the characteristics and systematics of intrinsic diffusion. This is done, both in a general context and in terms of problems and features more specifically associated with α-Zr. Among the latter are the anisotropic crystal structure, the limited temperature interval of α-phase stability, imposed by the α-β (hcp-bcc) transformation, and the tendency for Zr to have high residual impurity levels. It is emphasized that reliable, intrinsic, diffusion data can only be obtained through the use of high-purity single-crystal material. Vacancy diffusion is considered in terms of experimental data on irradiation damage. Solute effects on irradiation damage are discussed on the basis of the interactions of solutes with vacancies and self-interstitial atoms (SIA). (orig./MM)

[en] Samples of annealed sponge and crystal-bar Zr and Zircaloy-2 have been examined following irradiation in EBR-II at temperatures ≅ 700 K. Loop analysis shows that there is selective denuding of interstitial loops near to some grain boundaries indicating that such boundaries are net sinks for interstitial point defects. Furthermore, in sponge Zr and Zircaloy-2, vacancy c-component loops are observed running into the grain boundaries showing that the grain boundaries are not preferred sinks for vacancies. Cavities are observed in all samples. In crystal-bar Zr and sponge Zr they are mostly observed adjacent to grain boundaries. They are also sometimes found within grains associated with precipitates. The cavities are more common in the crystal-bar Zr and this is probably because both the sponge Zr and Zircaloy-2 contain vacancy c-component loops which compete for vacancies (assuming that the cavities are vacancy sinks). Only some of the grain boundaries have cavities adjacent to them and this may be related to the orientation of the boundary. (orig.)

[en] The development of quantitative information concerning the stabilities of uranium and thorium intermetallic compounds since the publication of Rough and Bauer's phase diagram compilation are reviewed. During this era a number of high temperature measurement techniques have been developed, from gas/solid equilibration to mass spectrometry and from high temperature calorimetry to solid state electrochemistry, and the growth of quantitative information has run parallel to this evolution. The amount of experimental effort now appears to be declining, and the task presently of major importance is to integrate and rationalize the quantitative information, an effort which will undoubtedly lead to new experimental initiatives. (orig.)

[en] Modeling methods are developed here to obtain a generalized approach across the periodic table for calculating C_p for the metallic elements. A Debye model is used for the harmonic lattice vibration contributions with the Debye temperature given by an expression of the form θ_D=θ₀[1-exp(-C₀/T)+exp(-C_∞/T)]. Expressions are also developed to describe the temperature dependent behavior of the dilatation and electronic contributions to C_p. The average deviation between calculation and experiment is found to be ±1.6% for C_p,₂₉₈ and ±1.0% for derived values S⁰₂₉₈. (orig.)

[en] The enthalpy of sublimation for the reaction PuF₃(s)→PuF₃(g) over the range 1127 to 1280 K was measured to be 413.8±16.4kJ/mol for the PuF₂⁺/PuF₃ ion intensity and 412.0±35.7kJ/mol for the PuF₃⁺/PuF₃ ion intensity. Combining this data with the measurements of other investigators gives ΔH_s⁰(298 K)=429.5±4.7 kJ/mol for the enthalpy of sublimation of PuF₃(s). (orig.)

[en] Fatigue tests in vacuum were carried out on the Manet heat of DIN 1.4914 martensitic steel (X13Cr10.7Ni0.85Mo0.75V0.22) in push-pull type, stress-controlled experiments at room temperature and 823 K. The fatigue life was determined as a function of stress amplitude, mean stress, frequency and hold time. At 823 K creep has a strong influence on the life time, particularly at low frequencies and long hold times in tension. The results are phenomenologically described by a simple linear damage summation approach. Even at room temperature the life time of specimens tested in vacuum is about an order of magnitude higher than of those tested in air. This stresses the importance of providing the correct test environment in collecting fatigue data for the design of fusion devices. (orig./MM)

[en] We argue that the micro-cleavage cracks observed in silicon crystals grown in a hydrogen-containing atmosphere and the [111] platelets observed in plasma- and reactive-ion-etched silicon are related and are responsible for the hydrogen embrittlement of silicon. We present our preliminary quantum mechanical calculations on model clusters of silicon using the modified neglect of differential overlap (MINDO/3) technique which support our argument. (orig.)

[en] Analysis and discussion are given of the radiation rate dependence of each component reaction process in the microstructure evolution under irradiation with energetic particles. The criteria to have radiation rate dependence are discussed from a relaxation time analysis of component phenomena (typically the time for defects to disappear to sinks) in which the overlap of component processes is the origin of the dependence. Examples for electron and neutron irradiation in at presently available facilities are presented, and the disappearance of the rate dependence by the saturation of defect structure development is pointed out. Enhancement and suppression of the defect structure development by accelerated irradiation are categorized from the pseudo-order of reaction of each component process. A typical example of a combination of component processes is presented for the dislocation loop formation by electron irradiation with a high voltage electron microscope. Several other sources of the rate dependence, such as cascade relaxation and the reaction of transmutation products, are pointed out. (orig.)

[en] Effects of hydrogenation on the core and valence electronic structures of β(bcc)-stabilized Ti-25at%V, Ti-50at%Nb and Ti-20at%Mo alloys are studied with XPS technique using monochromatized Al K_α radiation. Small but uniform binding-energy shifts are observed upon hydrogenation for all the core spectra measured. Their valence-band spectra are significantly distorted, providing an evidence of the formation of metal-hydrogen bonding bands in these Ti alloys. Interrelations between the core binding-energy shifts and the valence-band distortion are discussed. (orig.)