The second-generation composite materials were added to increase the strain to failure of the primary phase and/or create a dispersed second phase, thereby enhancing the fracture toughness of the thermosetting matrix. These matrices offered novel design capabilities for composites in a variety of aircraft applications. To improve the damage tolerance of composite materials even further, an engineering approach to toughening was used to modify the highly stressed interlayer with either a tougher material or through the use of preformed particles, leading to the third generation of composite materials. This chapter discusses the development, processes, application, advantages, and disadvantages of dispersed-phase toughening of thermoset matrices. Information on the processes of particle interlayer toughening of composite materials is also included.

As fiber-reinforced polymeric composites continue to be used in more damage-prone environments, it is necessary to understand the response of these materials when subjected to impact from foreign objects. This chapter provides an overview of the analysis methods for impact-damaged composites. It discusses the causes and effects of various failure mechanisms in composite materials. The failure mechanisms covered are brittle-matrix composite failure, tough-matrix composite failure, thermoplastic-matrix composite failure mechanisms, untoughened thermoset-matrix composite failure mechanisms, toughened thermoset-matrix composite failure mechanisms, particle interlayer-toughened composite failure mechanisms, and dispersed-phase, rubber-toughened thermoset-matrix composite failure mechanisms.

This chapter provides a general description of materials and methods for manufacturing high-performance composites. The materials covered are polymer matrices and prepreg materials and the methods include infusion processes, composite-toughening methods, matrix-toughening methods, and dispersed-phase toughening. In addition, the chapter provides information on interlayer-toughened composites and honeycomb or foam structure composite materials. It also discusses the processes in optical microscopy of composite materials.

This chapter discusses the use of thermoset and thermoplastic resins in polymer matrix composites. It begins by explaining how the two classes of polymer differ and how it impacts their use as matrix materials. It then goes on to describe the characteristics of polyester, vinyl ester, epoxy, bismaleimide, cyanate ester, polyimide, and phenolic resins and various toughening methods. The chapter also covers thermoplastic matrix materials and product forms and provides an introduction to the physiochemical tests used to characterize resins and cured laminates.

Ceramics normally have high melting temperatures, excellent chemical stability and, due to the absence of conduction electrons, tend to be good electrical and thermal insulators. They are also inherently hard and brittle, and when loaded in tension, have almost no tolerance for flaws. This chapter describes the applications, properties, and behaviors of some of the more widely used structural ceramics, including alumina, aluminum titanate, silicon carbide, silicon nitride, zirconia, zirconia-toughened alumina (ZTA), magnesia-partially stabilized zirconia (Mg-PSZ), and yttria-tetragonal zirconia polycrystalline (Y-TZP). It also provides information on materials selection, design optimization, and joining methods, and covers every step of the ceramic production process.

The formation of microcracks in composite materials may arise from static-, dynamic-, impact-, or fatigue-loading situations and also by temperature changes or thermal cycles. This chapter discusses the processes involved in the various methods for the microcrack analysis of composite materials, namely bright-field analysis, polarized-light analysis, contrast dyes analysis, and dark-field analysis. The analysis of microcracked composites using epi-fluorescence is also covered. In addition, the chapter describes the procedures for the determination and recording of microcracks in composite materials.

The analysis of composite materials using optical microscopy is a process that can be made easy and efficient with only a few contrast methods and preparation techniques. This chapter is intended to provide information that will help an investigator select the appropriate microscopy technique for the specific analysis objectives with a given composite material. The chapter opens with a discussion of macrophotography and microscope alignment, and then goes on to describe various illumination techniques that are useful for specific analysis requirements. These techniques include bright-field illumination, dark-field illumination, polarized-light microscopy, interference and contrast microscopy, and fluorescence microscopy. The chapter also provides a discussion of sample preparation materials such as dyes, etchants, and stains for the analysis of composite materials using optical microscopy.

Transmitted-light methods reveal more details of the morphology of fiber-reinforced polymeric composites than are observable using any other available microscopy techniques. This chapter describes the various aspects relating to the selection and preparation of ultrathin-section specimens of fiber-reinforced polymeric composites for examination by transmitted-light microscopy techniques. The preparation steps covered are a selection of the rough section, preparation of the rough section for preliminary mounting, grinding and polishing the primary-mount first surface, mounting the first surface on a glass slide, and preparing the second surface (top surface). The optimization of microscope conditions and analysis of specimens by microscopy techniques are also covered. In addition, examples of composite ultrathin sections that are analyzed using transmitted-light microscopy contrast methods are shown throughout.

In contrast to most plastic deformation processes, the shape of a machined component is not uniquely defined by the tooling. Instead, it is affected by complex interactions between tool geometry, material properties, and frictional stresses and is further complicated by tool wear. This chapter covers the mechanics and tribology of metal cutting processes. It discusses the factors that influence chip formation, including tool and process geometry, cutting forces and speeds, temperature, and stress distribution. It reviews the causes and effects of tool wear and explains how to predict and extend the life of cutting tools based on the material of construction, the use of cutting fluids, and the means of lubrication. It presents various methods for evaluating workpiece materials, chip formation, wear, and surface finish in cutting processes such as turning, milling, and drilling. It also discusses the mechanics and tribology of surface grinding and other forms of abrasive machining.

This article describes key processing methods and related design, manufacturing, and application considerations for plastic parts and includes a discussion on materials and process selection methodology for plastics. The discussion covers the primary plastic processing methods and how each process influences part design and the properties of the plastic part. It also includes a brief description of functional requirements in process selection; an overview of various process effects and how they affect the functions and properties of the part; and the selection of processes for size, shape, and design detail factors.