This chapter discusses the effect of powder metallurgy on the design and production of nuclear energy reactors, wind turbines, biomedical devices, and gas turbine engines.

This chapter describes aluminum applications in aircraft and space vehicles and the special alloys, tempers, and product forms required to meet the unique challenges of flight. It focuses on wrought alloys and products that comprise the bulk of aluminum aircraft structure. The chapter also provides a list of the aerospace alloys and their chemical compositions in common use as well as their application on aircraft.

This chapter discusses the development of aluminum, its industry growth, and its modern uses in manufacturing. It begins with the biography of Charles Martin Hall, who invented the process for reducing aluminum from its ore. The evolution of aluminum production from the Pittsburgh Reduction Company to a pilot plant on Smallman Street in Pittsburgh, to a production plant in New Kensington, and to Niagara Falls, New York, is then described. This is followed by a discussion on early aluminum applications and the usage of lower-cost raw materials. The chapter provides information on aluminum production process integrated by Aluminum Company of America (Alcoa) and the numerous technical problems and solutions related to Alcoa's research from World War I to World War II. The aerospace applications for aluminum alloys are also presented. The chapter concludes with a section on aluminum alloys developed by Alcoa.

High-pressure cold spray repair process has been used on a number of different applications in the defense industry. This chapter describes various applications for cold spray systems that have operating pressures greater than 2.4 MPa (350 psi) and operating temperatures greater than 500 deg C (930 deg F).

This chapter focuses on high-pressure cold spray applications pertaining to repair and refurbishment in the aerospace, oil and gas, and power-generation industries, the last specifically involving repair of gas turbine components. Advantages of cold spray coating in the repair and refurbishment of structural engineering components are also discussed.

Induction heat treating is used in a wide range of applications. Typical uses, as described in this chapter, include the surface hardening of many types of shafts as well as gears and sprockets and the through-hardening of gripping teeth, cutting edges, and impact zones incorporated into various types of tools and track pins manufactured for off-highway equipment.

This chapter describes the applications with the greatest impact on titanium consumption and global market trends. It explains where, how, and why titanium alloys are used in aerospace, automotive, chemical processing, medical, and military applications as well as power generating equipment, sporting goods, oil and gas production, and marine vessels.

The technology of fabricating composite hardware and structures by filament winding has evolved empirically through the development and manufacturing of specific components. This chapter reviews areas of technology used in building composite parts and discusses the processes from which the current technology was derived. The discussion covers quality control requirements for composite fabrication technology and cleanliness standards in the workplace. It describes technology developed for specific components, including satellites struts, aircraft hydraulic cylinders, drill pipe, drive shafts, couplings, and cryogenic tubing.

This chapter explains how the authors assessed the potential risks of creep-fatigue in several aerospace applications using the tools and techniques presented in earlier chapters. It begins by identifying the fatigue regimes encountered in the main engines of the Space Shuttle. It then describes the types of damage observed in engine components and the methods used to mitigate problems. It also discusses the results of analyses that led to changes in design or approach and examines fatigue-related issues in turbine engines used in commercial aircraft.

This chapter presents various case histories that illustrate a variety of failure mechanisms experienced by the high-strength steel components in aerospace applications. The components covered are catapult holdback bar, AISI 420 stainless steel roll pin, main landing gear (MLG) lever, inboard flap hinge bolt, nose landing gear piston axle, multiple-leg aircraft-handling sling, aircraft hoist sling, internal spur gear, and MLG axle. In addition, the chapter provides information on full-scale fatigue testing, nondestructive testing, and failure analysis of fin attach bolts.

This chapter deals with the effects of fatigue in rotating shafts subjected to elastic and plastic strains associated with bending stresses. It begins with a review of the basic approach to treating low-cycle fatigue in bending, explaining that the assumption that stress is proportional to strain is incorrect due to plastic flow, causing considerable discrepancy between measured and calculated stresses. Data plots of the axial and bending fatigue characteristics of a 4130 steel help illustrate the problem. A closed-form solution is then presented and used to analyze the effects of flexural bending on solid as well as hollow rectangular and round bars. The chapter also discusses the difference in the treatment of a rotating shaft in which all surface elements undergo the same stress and strain and a nonrotating shaft in which a few surface elements carry most of the load. The difference, as explained, is due to the volumetric effect of stress in fatigue.

This chapter identifies the primary causes of service failures and discusses the types of defects from which they stem. It presents more than a dozen examples of failures attributed to such causes as design defects, material defects, and manufacturing or processing defects as well as assembly errors, abnormal operating conditions, and inadequate maintenance. It also describes the precise usage of terms such as defect, flaw, imperfection, and discontinuity.

This chapter describes the characteristic damage of a mid-air explosion and how it appears in metal debris recovered from crash sites of downed aircraft. It explains that explosive forces produce telltale signs such as petaling, curling, spalling, spikes, reverse slant fractures, and metal deposits. Explosive forces can also cause ductile metals such as aluminum to disintegrate into tiny pieces and are associated with chemicals that leave residues along with numerous craters on metal surfaces. The chapter provides examples of the different types of damage as revealed in the investigation of two in-flight bombings.

A low-pressure turbine rotor blade failed in service, causing extensive engine damage. A section of the blade broke off around 25 mm from the root platform, producing a flat fracture surface that appeared smooth on one end and grainy elsewhere. Based on their examination, investigators concluded that the nickel-base superalloy blade was exposed to high temperatures and stresses, initiating a crack that propagated under cyclic loading. This chapter provides a summary of the investigation and the insights acquired using scanning electron fractography, metallography, and hardness measurements.

This chapter documents the key findings of an investigation into the failure of an aircraft’s main wheel bearing housing. Using annotated images and a detailed SEM fractograph, it shows what investigators observed that led them to conclude that the flange on one of the hubs broke off due to a combination of fatigue, bending stresses, and wear. It also includes a recommendation to assess the structural integrity of the bearing housing after every 100 h of service using nondestructive techniques.

An adaptor and a bolt were overloaded during a flight causing them to fracture. This chapter recounts the circumstances that led to the failure and the investigation that followed. It includes images of the fracture surfaces which show that both components failed quickly due to overload conditions. It also recommends the use of twin suspension hooks to make attachment points more stable under difficult flight conditions.