Author
W. Beere
Bio: W. Beere is an academic researcher from Central Electricity Generating Board. The author has contributed to research in topics: Grain boundary & Creep. The author has an hindex of 5, co-authored 5 publications receiving 130 citations.
Papers
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91 citations
11 citations
11 citations
TL;DR: In this article, the interaction of a migrating grain boundary in copper with microscopic helium bubbles was observed using an electron microscope, and it was shown that the bubble increased noticeably in size on contact with the boundary.
11 citations
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TL;DR: A review of the current understanding of the flow of superplastic metals and ceramics can be found in this paper, where a minor modification to the present definition of super-plasticity is proposed.
Abstract: On this seventy-fifth anniversary of the first scientific report of true superplastic flow, it is appropriate both to look back and examine the major developments that established the present understanding of superplasticity and to look to the future to the new opportunities that are made possible by new processing techniques, based on the application of severe plastic deformation, that permit the production of fully dense bulk materials with submicrometer or nanometer grain sizes. This review proposes a minor modification to the present definition of superplasticity, it provides an overview of the current understanding of the flow of superplastic metals and ceramics and then it examines, and gives examples of, the new possibilities that are now available for achieving exceptional superplastic behavior.
340 citations
TL;DR: In this paper, a review of the mechanisms and the anticipated rates of helium generation in fusion materials are discussed; helium introduction techniques simulating fusion conditions are reviewed in some detail and the atomistic behaviour of helium in metals as well as the nucleation and growth of helium bubbles are briefly surveyed.
Abstract: Radiation-induced deterioration of fission reactor materials is dominated by displacement damage. In fusion reactors, the influence of (n, α) produced helium upon material deterioration is regarded to be of equal importance because of the high nuclear reaction rate caused by the high-energy fusion neutrons. In this review, the mechanisms and the anticipated rates of helium generation in fusion materials are discussed; helium introduction techniques simulating fusion conditions are reviewed in some detail and the atomistic behaviour of helium in metals as well as the nucleation and growth of helium bubbles are briefly surveyed. These phenomena are the main cause for the influence of helium on macroscopic material properties such as tensile strength, creep and fatigue behaviour and swelling. Typical examples of experimental results of material deterioration and first attempts at their theoretical modelling are given in the main part of the review. It is shown that helium effects can be the determining factor for the lifetime of fusion reactor components, particularly at high temperatures. The review concludes with an outlook on future investigations of helium effects and a call for a systematic approach in the development of helium-resistant alloys.
319 citations
TL;DR: A review of the state-of-the-art of the understanding of cavity formation during stages I and II (primary and secondary) creep in polycrystalline metals and alloys, particularly at elevated temperatures, can be found in this article.
312 citations
TL;DR: Sintering occurs when packed particles are heated to a temperature where there is sufficient atomic motion to grow bonds between the particles as mentioned in this paper, and the conditions that induce sintering depend on the material, its melting temperature, particle size, and a host of processing variables.
Abstract: Sintering occurs when packed particles are heated to a temperature where there is sufficient atomic motion to grow bonds between the particles The conditions that induce sintering depend on the material, its melting temperature, particle size, and a host of processing variables It is common for sintering to produce a dimensional change, typically shrinkage, where the powder compact densifies, leading to significant strengthening Microstructure coarsening is inherent to sintering, most evident as grain growth, but it is common for pore growth to occur as density increases During coarsening, the grain structure converges to a self-similar character seen in both the grain shape distribution and grain size distribution Coarsening behavior during sintering conforms to classic grain growth kinetics, modified to reflect the evolving microstructure These modifications involve the grain boundary coverage due to pores, liquid films, or second phases and the altered grain boundary mobility due to these phases
226 citations
TL;DR: In this paper, the authors considered the diffusive cavitation of grain facets in circumstances for which the cavitated facets are well separated from one another, and showed that the rupture time tr, is given by the sum of two terms, one proportional to 1 Dσ ∞ (where D is the grain boundary diffusion parameter and σ∞ the stress which would act on a non-cavitated facet) and another proportional to E ∞(here E∞ is the creep rate of a similarly loaded polycrystal with uncavitated boundaries).
224 citations