REFRACTORY METAL ALLOYS Metallurgy and Technology

Transcription

1 REFRACTORY METAL ALLOYS Metallurgy and Technology

2 Editors I. Machlin Materials and Processes Branch Naval Air Systems Command Departrn.ent of the Navy Washington, D.C. R. T. Begley Astronuclear Laboratory Westinghouse Electric Company Pittsburgh, Pennsylvania atnd E. D. Weisert Materials Research Rocketdyne Division North American Rockwell CompOh/,y Canoga Park, California

3 '$i1yot~~ A Publication of The Metallurgical Society of AIME REFRACTORY METAL ALLOYS Metallurgy and Technology Proceedings of a Symposium on Metallurgy and Technology of Refractory Metals held in Washington, D.C., April 25-26, Sponsored by the Refractory Metals Committee, Institute of Metals Division, The Metallurgical Society of AIME and the National Aeronautics and Space Administration, Washington, D.C. <±> PLENUM PRESS NEW YORK 1968

4 ISBN ISBN (ebook) / American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. Softcover reprint of the hardcover I st edition 1968 Library of Congress Catalog Card Number Plenum Press is a division of Plenum Publishing Corporation 227 West 17 Street, New York, N. Y.10011

5 Preface This publication documents Proceedings of the Symposium on Metallurgy 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 melting temperature of over 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. Of eleven metals with melting points above 35000F, four have been advanced significantly in recent years, as bases for structural alloys, namely Cb, Mo, Ta, and W. The remaining seven (Re, 8f, Ir, Rh, Ru, Tc and Os) have received lesser development, a fact reflected in the Symposium program. Perhaps future Symposia will show a different emphasis. At the time of the first High Temperature Materials Conference in 1957 (Cleveland, Ohio) only the Mo-O.5% T1 alloy was in commercial production. Currently (1968) several dozen useful Cb, Mo, Ta, and W alloys have evolved, with many obtainable in good quality as sheet, foil, tube, wire, bar, and forgings. Although complete information on aerospace, nuclear, and commercial applications was not available for presentation at the SympoSium, it appears that refractory metals are serving essential structural functions, predominantly in prototype studies of propulsion, power generation, and hypersonic flight devices, with few requirements involving large quantities. A major factor limiting the utility of refractory metals in high temperature processes continues to be the lack of alloys (coated or otherwise) reliably operable for long times (multi-hundreds ofbours) in oxidizing environments. Nonetheless, there are several environments in which refractory metals are optimum materials, including vacua, inert gases, and liquid alkali metals. In oxidizing environments coated refrac~ory metals can serve for limited periods, under appropriate conv

6 vi PREFACE ditions. The U. S. capability in refractory metals for structural uses has been attained with Government support. supplemented by industry. of programs ranging from basic research to fabrication of hardware. Much work remains. if desired improvements in oxidation-resistance. strength. ductility. weldability and fabricability are to be attained. However, it appears likely that research efforts. in the future, will be selectively directed towards solving those critical problems limiting the useful potential of refractory metals. The invited papers in this publication were intended to provide maximum information required in judging future needs and research directions. We are grateful to the National Aeronautics and Space Administration for support enabling us to publish these proceedings. Much credit is due to authors of papers, who have made significant professional contributions by directing many hours of their leisure time to hard work. Our thanks are also extended to session chairmen and to members of the Refractory Metals Committee. who participated in organizing this Symposium. Distribution of this book in a timely and economical manner has been facilitated by photographic reproduction of authors' manuscripts, a procedure necessitating some relaxation of standards for editorial uniformity and format. We trust that the advantage of timely publication will outweigh perfection of format. It is regretted that the following planned papers were not available: Refractory Metals in Aerospace Structures, Use of Refractory Metals in Aerospace PropulSion, and Molybdenum and Molybdenum-Base-Alloys-Recent Developments. April Hachlin R. T. Begley E. D. Weisert

7 Contents Basic Strengthening Mechanism in Refractory Metals 1 B. A. Wilcox High Temperature Creep and Fracture Behavior of the Refractory Metals R. T. Begley, D. L. Harrod, and R. E. Gold The Effect of Thermal-Mechanical Treatments on the Structure and Properties of Refractory Metals 85 R. A. Perkins Interactions in Coated Refractory Metal Systems ~ A. G. Metcalfe and A. R. Stetson Interactions of Refractory Metals with Active Gases in Vacua and Inert Gas Environments 165 H. Inouye Hydrogen Effects in Refractory Metals W. T. Chandler and R. J. Walter 197 The Compatibility of Refractory Metals with Liquid Metals 251 E. E. Hoffman and R. W. Harrison Refractory Metals in Space Electric Power Conversion Systems 289 J. W. Semmel, Jr. Recent Advances in Columbium Alloys R. G. Frank 325 Considerations in the Development of Tantalum Base Alloys 373 R. W. Buckman, Jr. and R. C. Goodspeed Advanced Processing Technology and High Temperature Mechanical Properties of Tungsten Base Alloys 395 H. G. Sell vii

8 viii CONTENTS The Less Common Refractory Metals (Rhenium, Technetium, Hafnium, Noble Metals) 451 J. Maltz Index 0 0 " " " 0 0 " 0 0 " 0 0 " " "