This article emphasizes the physical metallurgy of titanium and titanium alloys along with their microstructural response to fusion welding condition. The titanium alloys are classified into unalloyed or commercially pure titanium, alpha and near-alpha alloys, alpha-beta alloys, and metastable beta alloys. The article further discusses the weld microstructure for alpha-beta and metastable beta alloys and describes welding defects observed in titanium alloys. The influence of macro- and microstructural characteristics of titanium weldment on mechanical properties is also discussed. The article concludes with a discussion on the different welding processes used in the welding of titanium and titanium alloys.

This article focuses on the physical metallurgy and weldability of four families of titanium-base alloys, namely, near-alpha alloy, alpha-beta alloy, near-beta, or metastable-beta alloy, and titanium based intermetallics that include alpha-2, gamma, and orthorhombic systems.

This article introduces the different types, distinctions, and grades of commercially pure titanium and titanium alloys. It describes three types of alloying elements: alpha stabilizers, beta stabilizers, and neutral additions. The article discusses the basic categories of titanium alloys, namely, alpha and near-alpha titanium alloys, beta and near-beta titanium alloys, and alpha-beta titanium alloys. It also describes the general microstructural features of titanium alloys.

This article summarizes the metallurgical and environmental variables that affect fracture toughness, fatigue life, and subcritical crack growth of titanium alloys, such as chemistry, microstructure, texture, environment, and loading. The classes of titanium alloys considered in the article include alpha-beta alloys, Ti-6AI-4V; alpha alloys, Ti-8Al -1Mo-IV, Ti-5AI-2.5Sn, Ti-6242S; and beta alloys, solute-lean beta alloys and solute-rich beta alloys.

Commercially pure titanium and most titanium alloys can be welded by procedures and equipment used in welding austenitic stainless steel and aluminum. This article describes weldability of unalloyed titanium and all alpha titanium alloys. It reviews the selection of fusion-welding processes that are used for joining titanium and titanium alloys. The processes include gas-tungsten arc welding (GTAW), gas-metal arc welding (GMAW), plasma arc welding (PAW), electron-beam welding (EBW), laser-beam welding (LBW), friction welding (FRW), and resistance welding (RW). The article discusses the role of filler metals and shielding gases in welding titanium and titanium alloys. It describes the equipment used for gas-tungsten arc welding and concludes with information on repair welds.

This article describes different types of titanium alloys, including alloy Ti-6Al-4V, alpha and near-alpha alloys, and alpha-beta alloys. It explains the formability of titanium alloys with an emphasis on the Bauschinger effect. The article provides information on the tool materials and lubricants used in the forming process. It provides information on the cold and hot forming, superplastic forming, and combination of superplastic forming/diffusion bonding. The article discusses the various forming processes of these titanium alloys, including press-brake forming, power (shear) spinning, rubber-pad forming, stretch forming, contour roll forming, creep forming, vacuum forming, drop hammer forming, joggling, and explosive forming.

Titanium and its alloys have been used extensively in a wide variety of implant applications, such as artificial heart pumps, pacemaker cases, heart valve parts, and load-bearing bone or hip joint replacements or bone splints. This article discusses the properties of titanium and its alloys and presents a list of titanium-base biomaterials. Titanium components are produced in wrought, cast, and powder metallurgy (PM) form. The article describes forging, casting, and heat treating of titanium alloys for producing titanium components. Typical mechanical properties of titanium biomedical implant alloys are listed in a tabular form. The article presents an overview of the surface-modification methods for titanium and its alloys implants. It concludes with a section on biocompatibility and in vivo corrosion of titanium alloys.

Quenching is a widely used technique to strengthen titanium alloys. This article presents the metallurgical and structural background underlying the specific techniques applied in the quenching of various titanium alloys, and the ways to control and reduce residual stresses induced from quenching or other thermal or mechanical processes. It discusses the types and microstructures of titanium alloys, namely, alpha, alpha-beta, and beta alloys, and describes the general effects of the various heat treatments. The article provides information on quenching media, quenching rate, section size, and martensitic transformation in quenched titanium alloys. It shows how residual stresses in titanium alloys are evaluated and controlled. Finally, the article describes the stress-relief treatments used to reduce residual stresses.

This article discusses the wrought product forms of titanium and titanium-base alloys, which include forgings and the typical mill products with tabulations for various specifications, and compares specifications for pure titanium, titanium alloys for mechanical, physical properties and chemical properties, including chemical composition, corrosion resistance, and chemical reactivity. The article discusses the effects of alloying elements in titanium alloys, and describes the classes of titanium alloys, namely, alpha alloys, alpha-beta alloys, and beta alloys. It also describes the typical applications of various titanium-base materials, and explains the crystal structure, effect of impurities, and microstructural constituents of titanium alloys. The article provides a brief description on the processing of wrought titanium alloys, including primary fabrication in which ingots are converted into general mill products and secondary fabrication (forging, extrusion, forming, machining, chemical milling and joining) of finished shapes from mill products and the heat treatment of titanium alloys.

This article provides a detailed discussion on the heat treatment processes for titanium and titanium alloys. These processes are age hardening, solution treatment, aging, and annealing. The article illustrates the characteristics of equilibrium phase diagrams that are important for understanding the heat treatment of titanium alloys. It explains the types of metastable phases encountered in titanium alloys. The article also provides information on the equilibrium phase relationships and properties of titanium alloys.

Titanium alloys are forged into a variety of shapes and types of forgings, with a broad range of final part forging design criteria based on the intended end-product application. This article begins with a discussion on the classes of titanium alloys, their forgeability, and factors affecting forgeability. It describes the forging techniques, equipment, and common processing elements associated with titanium alloy forging. The processing elements include the preparation of forging stock, preheating of the stock, die heating, lubrication, forging process, trimming and repair, cleaning, heat treatment, and inspection. The article presents a discussion on titanium alloy precision forgings and concludes with information on the forging of advanced titanium materials and titanium aluminides.

The response of titanium and titanium alloys to heat treatment depends on the composition of the metal, the effects of the alloying elements on the alpha-beta crystal transformation, and the thermomechanical processing utilized during processing of the alloy. This article provides a detailed discussion on the effects of heat treatment on the mechanical properties for three general classes of titanium alloys, namely, alpha and near-alpha titanium alloys, alpha-beta alloys, and beta alloys.

The thermomechanical processing (TMP) of conventional and advanced nickel and titanium-base alloys is aimed at altering or enhancing one or more metallurgical features within the material and component. This article presents a number of examples of the TMP of nickel-base superalloys and titanium alloys. The TMP techniques include retained-strain processing, dual-microstructure processing, and dual-alloy processing. The article also describes the TMP of alpha-beta titanium alloys, including fine-grain processing, hybrid-structure processing, dual-microstructure processing, and dual-alloy processing. It concludes with a discussion on computer simulation of advanced TMP processes.

This article describes the different types of precipitation and transformation processes and their effects that can occur during heat treatment of various nonferrous alloys. The nonferrous alloys are aluminum alloys, copper alloys, magnesium alloys, nickel alloys, titanium alloys, cobalt alloys, zinc alloys, and heat treatable silver alloys, gold alloys, lead alloys, and tin alloys. It also provides a detailed discussion on the effects due to precipitation and transformation processes in these non-ferrous alloys.

This article provides a background of the complex relationship between titanium and its alloys with aqueous environments, which is dictated by the presence of a passivating oxide film. It describes the corrosion vulnerability of titanium and titanium oxides by the classification of oxide failure mechanisms. The mechanisms are spatially localized oxide film breakdown by the ingress of aggressive anions; spatially local or homogenous chemical dissolution of the oxide in a strong reducing-acid environment; and mechanical disruptions or depassivation such as scratching, abrading, or fretting. Titanium alloys can be classified into three primary groups such as titanium alloys with hexagonal close-packed crystallographic structure; beta titanium alloys with body-centered cubic crystallographic structures; and alpha + beta titanium alloys including near-alpha and near-beta titanium alloys. The article also illustrates the effects of alloying on active anodic corrosion of titanium and repassivation behavior of titanium and titanium-base alloys.

The modeling and simulation of texture evolution for titanium alloys is often tightly coupled to microstructure evolution. This article focuses on a number of problems for titanium alloys in which such coupling is critical in the development of quantitative models. It discusses the phase equilibria, crystallography, and deformation behavior of titanium and titanium alloys. The article describes the modeling and simulation of recrystallization and grain growth of single-phase beta and single-phase alpha titanium. The deformation- and transformation-texture evolution of two-phase (alpha/beta) titanium alloys are also discussed.

This article describes the fundamentals of titanium metallographic sample preparation. Representative micrographs are presented for each class of titanium alloys, including unalloyed titanium, alpha alloys, alpha-beta alloys, and beta titanium alloys. The article provides information on the macroexamination and microexamination for these alloys. It concludes with a discussion on the several metallographic techniques developed for specific purposes, such as recrystallization studies and microstructure/fracture topography correlations.

This article focuses on the modeling of microstructure evolution during thermomechanical processing in the two-phase field for alpha/beta and beta titanium alloys. It also discusses the mechanisms of spheroidization, the coarsening, particle growth, and phase decomposition in titanium alloys, with their corresponding equations.

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.