Refractory Metals And Alloys Ii

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.

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.

Progress made in applying advanced techniques and structural concepts to the problem of strengthening the Group VI-A metals, Cr, Mo, and W, is examined. At low temperatures, T/Tm

Contents: Machining superalloys General information Effect of alloy condition on machinability Minimizing work-hardening tendencies of superalloys Turning and facing operations Milling operations Drilling operations Machining of refractory metals Tungsten Effect of surface contaminations on machine ability Molybdenum Effect of anisotropy, grain structure and prior work on machinability Tantalum and columbium Turning operations, milling operations Bibliography.