I NFORMATION ON REFRACTORY COMPOSITES FOR USE ABOVE

This report summarizes information on refractory composites for use above 2500 F, as presented at the Seventh Meeting of the Refractory Composites Working Group, held March 12-14, 1963. Reports presented at the meeting were concerned with pro tective coatings, insulating ceramics, materials for rocket thrust chambers, dispersion strength ening of metals, joining of refractory materials, and testing techniques. Emphasis in the field of coatings for refractory metals has shifted from the rudiments of developing oxidation-resistant coatings to improvement and advanced evaluation of coatings to predict their utility for re-entry vehicles. (Author).

Modern Materials: Advances in Development and Applications, Volume 5 provides comprehensive insight into the properties, applications, progress, and potentialities of various materials. This book is composed of four chapters, and begins with the presentation of the properties and application areas of coated refractory metals. The second chapter describes the special properties and utilization areas of hydrogen-precipitated powders and roll-compacted strip made from these metals and some of their related alloys. This chapter emphasizes the production processes of these materials. The third chapter deals first with a few general aspects of luminescence and phosphor synthesis, followed by significant discussions on the main fields of application of phosphors. The fourth chapter surveys concrete as an important construction material and its wide-array of application. This book is of great value to materials scientists and technologists.

This report summarizes the information generated since the middle of 1961 on the chemical, physical, and mechanical properties of refractory metals that are coated with oxidation-resistant coatings of advanced-experimental or commercial status. It is a supplement to DMIC Report 162, Coatings for the Protection of Refractory Metals from Oxidation, dated November 24, 1961. Recent data on specific silicide- and aluminide- type coatings for columbium, molybdenum, tantalum, and tungsten and their alloys reflect general advances in coating quality and performance, understanding of the behavior of coated systems, and more complete realization of the problems associated with the use of coated hardware.

This report is the third of a series which will periodically summarize the status of the various contracts involved in the Department of Defense Refractory Metals Sheet Rolling Program. Under this program, selected candidate materials are being carried through one or more of the following consecutive phases: Phase I, development of a sheet-production practice; Phase II, establishment of minimum design data; and Phase III, evaluation of sheetfabrication characteristics. To the present time, 13 contracts have been funded or planned in support of the Phase I, II, and III activities. This report summarizes the status of each of these individual contracts as of November 1, 1964. The first section describes the overall program of the Department of Defense Refractory Metals Sheet Rolling Program. Following, in the order of their discussions, are sections dealing with fabricable molybdenum alloys, unalloyed tungsten, columbium alloys, and tantalum alloys. (Author).

The report is a compilation of 36 papers describing the information discussed at the Thirteenth Refractory Composites Working Group Meeting held at The Olympic Hotel, Seattle, Washington on 18, 19, and 20 July 1967. Representatives of various organizations presented informal discussions of their current activities in the fields of development, evaluation and application of inorganic refractory composites for use in high temperature environments.

The properties of materials depend on the characteristics of the bulk and on those of the surf ace. Any change in surface characteristics affects a wide variety of material properties. During the last few years the role of surface phenomena in metallurgy has been the subject of many studies. Surface energy, surface tension, the activity of surfaces, and related problems are under discussion in the western world * as well as in the eastern world. t The relation between volume and surface properties in metals and alloys has been investigated and is still under investigation. Materials are frequently exposed to environments which change their physical and chemical characteristics on account of a reaction going on between the material surface and the environment. The science and technology of surface preparation ro improve material properties have gained importance during the last decade in many parts of the world. Main efforts have been concentrated especially on the coating of material surfaces in connection with the exposure of these materials to space en vironment.