Heat treatment of depleted uranium (DU) alloys with 4.0 wt% or more molybdenum or equivalent is similar to that of dilute alloys. This article discusses the metallurgical characteristics and processing considerations of DU and its alloys, and describes the control of grain size and orientation using beta treatment. It lists the typical mechanical properties of DU as functions of the amount of cold work and hardness data of uranium rod, and describes the annealing of cold-worked DU. The article also describes the heat treatment of dilute alloys of DU, focusing on the three basic furnace designs used for heating or heat treating of unalloyed uranium: molten salt baths, inert-atmosphere furnaces, and vacuum furnaces. Finally, it presents procedures that are examples of heat treatment used to meet certain specifications of ultimate tensile strength, yield strength, and elongation.

Uranium is a moderately strong and ductile metal that can be cast, formed, and welded by a variety of standard methods. This article presents an overview of the processing and properties of uranium and uranium alloys with a brief overview of the principal hazards and precautions associated with processing depleted uranium and methods to control mild radioactivity, chemical toxicity, and pyrophoricity. It also describes the classification and heat treatment of uranium and uranium alloys. Furthermore, the article provides graphical representation of the effect of alloy composition, cooling rate, and aging temperature on microstructure, crystal structure, and mechanical properties of uranium and uranium alloys.

This article reviews general corrosion of uranium and its alloys under atmospheric and aqueous exposure as well as with gaseous environments. It describes the dependence of uranium and uranium alloy corrosion on microstructure, alloying, solution chemistry, and temperature as well as galvanic interactions between uranium, its alloys, and other metals. The article provides information on the atmospheric corrosion of uranium based on oxidation in dry air or oxygen, water vapor, and oxygen-water vapor mixtures depending upon particular storage conditions. The mechanism and morphology of hydride corrosion of uranium are discussed. The article provides information on environmentally assisted cracking, protective coatings, and surface modification of uranium and its alloys. It also summarizes the environmental, safety, and health considerations for their use.

This article focuses on the basic metallurgy and machining parameters of classes of depleted and enriched uranium alloys. It provides information on the health precautions applicable to the machining of depleted uranium alloys. The article also discusses tool wear and the types of tools used in uranium alloy machining.

This article discusses the principles of physical metallurgy and metallography of depleted uranium. It describes the techniques involved in the preparation of thin foils for transmission electron microscopy and illustrates the resulting microstructure of uranium and uranium alloys, with the aid of black and white images. The article also provides information on the applications of etching and examination of uranium alloys, at both macro and micro scales, in characterizing the grain structures, segregation patterns, inclusions, and the metal flow geometries produced by solidification and mechanical working processes.

Very high density materials are used for such applications as counterweights and radiation shields. This article focuses on the metallurgy, processing, properties, fabrication, design considerations, health and safety considerations, and applications of the most commonly used very high density materials: depleted uranium and tungsten and their alloys.

This article is a compilation of binary alloy phase diagrams for which uranium (U) is the first named element in the binary pair. The diagrams are presented with element compositions in weight percent. The atomic percent compositions are given in a secondary scale. For each binary system, a table of crystallographic data is provided that includes the composition, Pearson symbol, space group, and prototype for each phase.

This article is a compilation of binary alloy phase diagrams for which rhodium (Rh) is the first named element in the binary pair. The diagrams are presented with element compositions in weight percent. The atomic percent compositions are given in a secondary scale. For each binary system, a table of crystallographic data is provided that includes the composition, Pearson symbol, space group, and prototype for each phase.

Controlled-potential coulometry is a highly precise and accurate method primarily used for major constituent analysis of analyte substances such as alloys, compounds, nonmetallic materials and organic compounds. This article illustrates the apparatus required for controlled-potential coulometry, and provides information on its techniques and applications. It contains a table that lists the metals for which accurate methods have been developed and the basic electrochemistry of the procedures. The article explains that gold and uranium are the elements that are determined frequently in various sample types.

Nuclear power plants benefit from thermal spray coatings for corrosion and erosion minimization and dimensional restoration of worn parts. This article provides a detailed discussion on the advantages of thermal spray coatings, fission reactor component coatings, and coatings for nuclear fuel processing before and after irradiation for power plant applications. Nuclear fusion research is divided into two primary fields of study categorized by the method for confining the fusion fuel: magnetic confinement fusion and inertial confinement fusion.

Molten salts, or fused salts, can cause corrosion by the solution of constituents of the container material, selective attack, pitting, electrochemical reactions, mass transport due to thermal gradients, and reaction of constituents and impurities of the molten salt with the container material. This article describes a test method performed using thermal convection loop for corrosion studies of molten salts. It discusses the purification of salts that are used in the Oak Ridge molten salt reactor experiment. The article also reviews the corrosion characteristics of nitrates/nitrites and fluoride salts with the aid of illustrations and equations.

Eutectoid and peritectoid transformations are classified as solid-state invariant transformations. This article focuses primarily on the structures from eutectoid transformations with emphasis on the classic iron-carbon system of steel. It reviews peritectoid phase equilibria that are very common in several binary systems. The addition of substitutional alloying elements causes the eutectoid composition and temperature to shift in the iron-carbon system. The article graphically illustrates the effect of various substitutional alloying elements on the eutectoid transformation temperature and effective carbon content. The partitioning effect of substitutional alloying elements, such as chromium, manganese, and silicon, in pearlitic steel is also illustrated.

This article provides an overview of the classification of hydrogen damage. Some specific types of the damage are hydrogen embrittlement, hydrogen-induced blistering, cracking from precipitation of internal hydrogen, hydrogen attack, and cracking from hydride formation. The article focuses on the types of hydrogen embrittlement that occur in all the major commercial metal and alloy systems, including stainless steels, nickel-base alloys, aluminum and aluminum alloys, titanium and titanium alloys, copper and copper alloys, and transition and refractory metals. The specific types of hydrogen embrittlement discussed include internal reversible hydrogen embrittlement, hydrogen environment embrittlement, and hydrogen reaction embrittlement. The article describes preservice and early-service fractures of commodity-grade steel components suspected of hydrogen embrittlement. Some prevention strategies for design and manufacturing problem-induced hydrogen embrittlement are also reviewed.

Hydrogen damage is a term used to designate a number of processes in metals by which the load-carrying capacity of the metal is reduced due to the presence of hydrogen. This article introduces the general forms of hydrogen damage and provides an overview of the different types of hydrogen damage in all the major commercial alloy systems. It covers the broader topic of hydrogen damage, which can be quite complex and technical in nature. The article focuses on failure analysis where hydrogen embrittlement of a steel component is suspected. It provides practical advice for the failure analysis practitioner or for someone who is contemplating procurement of a cost-effective failure analysis of commodity-grade components suspected of hydrogen embrittlement. Some prevention strategies for design and manufacturing problem-induced hydrogen embrittlement are also provided.

Solid-state transformations from invariant reactions are of three types: eutectoid, peritectoid, and monotectoid transformations. This article focuses on structures from eutectoid transformations with an emphasis on the classic iron-carbon system of steel. It illustrates the morphology of a pearlite nodule and the effect of various substitutional alloy elements on the eutectoid transformation temperature and effective carbon content, respectively. Peritectic and peritectoid phase equilibria are very common in several binary systems. The article reviews structures from peritectoid reactions and details the formation of peritectic structures that can occur by at least three mechanisms: peritectic reaction, peritectic transformation, and direct precipitation of beta from the melt.

Skull melting refers to the use of furnaces with water-cooled crucibles that freeze a solid “skull” of material on the crucible wall. This article describes the basic components, operating pressure, advantages, and applications of vacuum arc and induction skull melting furnaces.

Coextrusion is defined as the simultaneous extrusion of two or more metals to form an integral product that can be carried out using conventional extrusion or drawing equipment at a temperature appropriate to the metal system being formed. This article discusses the applications, billet configurations, and metal flow modes of coextrusion. It presents the analytical studies of coextrusion: deformation energy methods, lower-bound (slab) analyses, upper-bound analyses, and finite-element analyses. These studies are used to identify the regime of material properties and process variables for which sound extrusions can be obtained. The article concludes with a discussion on the state-of-the-art of coextrusion that assists in developing process models, which accurately describe both the macroscopic and microscopic aspects of a process.

Soft-interlayer solid-state welds that join stronger base metals have unique mechanical properties that are of fundamental interest and may be of critical importance to designers. This article discusses the mechanical properties of soft-interlayer solid-state welds and the implications of these behaviors to service stress states and environments. It describes the tensile loading of soft-Interlayer welds in terms of the effect of interlayer thickness on stress, interlayer strain, time-dependent failure, effect of base-metal properties, and effect of interlayer fabrication method. The article concludes with a discussion on multiaxial loading.

This article discusses the mechanical properties of soft-interlayer solid-state welds and the implications of these behaviors to service stress states and environments. It illustrates the microstructure of as-deposited coatings and solid-state-welded interlayers. The article reviews factors that affect the tensile loading of strength of soft-interlayer welds: the interlayer thickness, the interlayer strain, and the interlayer fabrication method. It also provides information on stress-corrosion cracking of interlayers and stress behavior of these interlayers during shear and multiaxial loading.

Metallographic preparation of a material involves the elimination of artifacts or scratches from fine polishing and may be achieved by methods such as attack polishing, vibratory polishing, chemical polishing, electrolytic polishing, and electromechanical polishing. This article discusses the mechanism, operating procedure, advantages, and limitations of chemical and electrolytic polishing of samples for metallographic preparation. It provides information on the specimen preparation, apparatus used, and safety precautions to be followed during the polishing process. The various groups of electrolytes used in electropolishing of several metals and alloys are reviewed. The article concludes with a discussion on local electropolishing.