Strain Aging of Refractory Metals (tantalum).
Strain Aging of Refractory Metals (tantalum).

Author: W. Eliasz

Publisher:

Published: 1965

Total Pages: 111

ISBN-13:

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Strain aging effects in electron-beam refined tantalum have been studied using the yield point return and internal friction technique. The results have been discussed with reference to current theories of strain aging. A comparison of the data obtained by both techniques has been made which shows that the internal friction technique yields more direct information about the interstitial impurity responsible for the strain aging process. Electron-beam refined tantalum, when tested at room temperature, shows strain-aging effects, which become measurable at aging temperature greater than about 70 C. The activation energy of the strain-aging process has been found to be 26,000 + or - 1,000 cal/mol which is of the order of the activation energy for the diffusion of oxygen in tantalum (25,500 cal/mol). The magnitude of the strain-aging effects have been shown to be dependent on the concentration of oxygen, and this appears to be due to increased strength of pinning of dislocations with increasing oxygen content. The increase in the yield stress caused by strain-aging has been found to be no only due to the change in dislocation locking parameter, k sub y, but also to the increase in flow stress. It has been shown that in the temperature range studied (100 - 200 C) oxygen is responsible for the strain-aging effects. At higher temperatures nitrogen and/or carbon can contribute to strain-aging too. (Author).

Refractory Metal Alloys Metallurgy and Technology
Refractory Metal Alloys Metallurgy and Technology

Author: I. Machlin

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 493

ISBN-13: 1468491202

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This publication documents Proceedings of the Symposium on Metal lurgy and Technology of Refractory Metal Alloys, held in Washington, D.C. at the Washington Hilton Hotel on April 25-26, 1968, under sponsorship of the Refractory Metals Committee, Institute of Metals Division, of the Metallurgical Society of AIME, and the National Aeronautics and Space Administration. The Symposium presented critical reviews of selected topics in refractory metal alloys, thereby contributing to an in-depth understanding of the state-of-the-art, and establishing a base line for further research, development, and application. This Symposium is fifth in a series of conferences on refractory metals, sponsored by the Metallurgical Society of AlME. Publications issuing from the conferences are valuable technical and historical source books, tracing the evolution of refractory metals from early laboratory alloying studies to their present status as useful engineering materials. Refractory metals are arbitrarily defined by melting point. A 0 melting temperature of over 3500 F was selected as the minimum for this Symposium, thus excluding chromium and vanadium, which logically could be treated with other refractory metals in Groups VA and VIA of the periodic table. The Refractory Metals Committee is planning reviews of chromium and vanadium in subsequent conferences.

Physical Metallurgy of Refractory Metals and Alloys
Physical Metallurgy of Refractory Metals and Alloys

Author: E. M. Savitskii

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 296

ISBN-13: 1468415727

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The principal reasons which induced the authors to write this book and the features of the book are set forth in the preface to the Russian edition. That section of the science of metals which in Russian is called "metallovedenie" or the "physical chemistry of metals" is generally referred to in scientific and technical literature published in the English language by the term "physical metallurgy." These concepts are much broader than the term" metallography," used in the scientific and technical literature of various countries, and applied solely to research on the interrelationships of the structure and proper ties of metals and alloys. Each science must have its own subject and its own method of research. Certainly, all specialists will agree that metals and alloys, including their solid solutions, mechanical mix tures, and metallic compounds, form the subject of "physical metallurgy" or "physical chemis try of metals." The aim of this science. is to produce a theory and to elucidate the experimental relationships which ought finally to make it possible to calculate quantitatively alloys Of given properties for any working conditions and parameters.