Since the combination of tensile properties and toughness that can be obtained with the maraging steels is higher than can be achieved with other steels by simple heat treatments, there is considerable interest in using the maraging steels for critical components such as rocket motor cases, pressure vessels, and aircraft forgings. This report includes information on the tensile, compressive, shear, bearing, dynamic modulus, impact, bend, fatigue, creep, and rupture properties of the 18 per cent nickel maraging steels and on the effect of temperature on these properties. Data for the properties of sheet, bar, and forgings, as well as data illustrating the effect of cold rolling, variation in the heat treatment, and elevated-temperature exposure also are presented. Data on the effect of specimen orientation, which are also included, indicate that the ductility and toughness of specimens designed to evaluate the properties in the short transverse direction are somewhat lower than in the other directions. The high strength and toughness that can be obtained in the 18 per cent nickel maraging steels make them attractive for certain critical applications that require these properties. The fabrication characteristics, weldability, and simple heat treatment are other advantages of these steels. (Author).

This report describes the characteristics and properties of existing commercial magnesium alloys and compares these relative to each other. Although this report is not intended to serve as a source of design data for magnesium alloys, it was written to provide a simple, up-to-date background of information for the technologist who is faced with the problem of materials selection and who is unfamiliar with the advantages and discaadvantages of magnesium alloys. The eight major alloying elements which are used to control the properties of magnesium are listed along with selected data illustrating the binary phase relationships which exist, between the hexagonal, close-packed structure of magnesium and each of these metals. The nomenclature system for commercial magnesium alloys is explained and compositions and available forms of the alloys are given. Property comparisons of both cast and wrought alloys are presented. There is a section in the report dealing with the joining, forming, and machining of magnesium, and a section devoted to a discussion of a number of finishing systems which have been developed for magnesium alloys. (Author).

Studies on the effects of heat-treating and testing environments for the refractory metals have been limited primarily to the unalloyed metals and a few alloys of columbium and molybdenum. Most of this work has relied on compositional changes as a means of assesing the effects of various environments on these materials. It has been shown that all of these materials are subject to contamination or purification in various test environments. The residual gases H2, CO(or N2), and H20, constitute the major sources of contamination when testing columbium and tantalum materials in vacua. Under the same conditions, molybdenum and molybdenum alloys containing carbon and reactive-metal additions are subject to serious decarburization. Nonreactive gaseous atmospheres also cause serious changes in material chemistry, since small quantities of noxious gases are contained in the atmosphere. Several promising methods of circumventing material chemistry changes during various longtime, high-temperature exposures are being used and/or evaluated. (Author).