Showing papers by "Vincent Ji published in 2000"
TL;DR: In this paper, an empirical relationship between the X-ray diffraction peak width and the conventional mechanical proprieties (hardness, elastic limit, hard work degree) for INCONEL 600 alloy was found.
Abstract: INCONEL 600 alloy is largely used as nuclear power center components. The non-destructive determination of the superficial mechanical proprieties is indispensable for the qualification of the fabrication process and for the service duration estimation in aggressive environment. X-ray diffraction (XRD) technique is non-destructive and can be used to determine microscopic internal stresses from the broadening of the XRD peaks. The average magnitude of XRD peak broadening is related directly to the hardness, the elastic limit or degree of cold work of the material which can be used as a means of quantifying the surface mechanical properties. With an empirical relationship between the {311} XRD peak width and the conventional mechanical proprieties (hardness, elastic limit, hard work degree) for INCONEL 600 alloy, the superficial mechanical characteristics can be estimated from diffraction peak width for just finished parts or for maintenance pieces. Several TEM observations are also realized for microstructure study.
15 citations
TL;DR: In this article, the authors used X-ray diffraction to evaluate the stress distribution in the copper coating and in the niobium subtrat, and developed an analytical calculation to understand the source of residuel stress and the experimental observations.
Abstract: Depuis trois ans, on etudie la possibilite de renforcer des cavites supraconductrices en niobium par un revetement de cuivre, realise par projection thermique. Celle-ci peut generer des contraintes residuelles relativement importantes dans le revetement et dans le substrat supraconducteur. L'analyse des contraintes residuelles s'avere donc necessaire. La methode de diffraction des rayons X est sans doute la plus utilisee pour determiner les contraintes residuelles. Dans notre etude, cette methode a permi de determiner la distribution de contrainte non seulement dans les revetements de cuivre mais aussi dans le substrat en niobium. C'est la premiere fois que ce genre d'analyse a ete realisee sur ce type de depot plasma. Un calcul analytique de contrainte thermique a ete developpe pour une geometrie particuliere: celle d'un tube. Il a permis d'eclaicir l'analyse sur l'origine des contraintes residuelles et d'interpreter les observations experimentales. Since last three years, we study the possibility to stiffen the niobium superconducting cavities by thermal sprayed copper coating. The important residuel stress could been generated in the copper coating and in the superconducting substrat of niobium after thermal projection, the analysis of residuel stress is necessary, The X-ray diffraction method is often used to determinate the residuel stress. In the work, the X-ray diffraction is used to evaluate the stress distribution in the copper coating and in the niobium subtrat. This kind of analysis for a copper coating realized onto a niobium substrat have never been determinated before, so the results of this work are news. An analytical calculation have been developed to understand the source of residuel stress and the experimental observations.
2 citations