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.

Basic Strengthening Mechanism in Refractory Metals.- High Temperature Creep and Fracture Behavior of the Refractory Metals.- The Effect of Thermal-Mechanical Treatments on the Structure and Properties of Refractory Metals.- Interactions in Coated Refractory Metal Systems.- Interactions of Refractory Metals with Active Gases in Vacua and Inert Gas Environments.- Hydrogen Effects in Refractory Metals.- The Compatibility of Refractory Metals with Liquid Metals.- Refractory Metals in Space Electric Power Conversion Systems.- Recent Advances in Columbium Alloys.- Considerations in the Development of Tantalum Base Alloys.- Advanced Processing Technology and High Temperature Mechanical Properties of Tungsten Base Alloys.- The Less Common Refractory Metals (Rhenium, Technetium, Hafnium, Noble Metals).