This article introduces procedures an engineer or materials scientist can use to investigate failures. It provides a brief survey of polymer systems and key properties that need to be measured during failure analysis. The article begins with an overview of the problem-solving approach pertinent to structure analysis. This is followed by a review of the characterization of plastics by infrared and nuclear magnetic resonance spectroscopy. The article then provides information on the distribution of molecular weight of an engineering plastic. It further discusses the methods used in thermal analysis, namely differential thermal analysis, thermogravimetric analysis, thermal-mechanical analysis, and dynamic mechanical analysis. The following sections provide details on X-ray diffraction for analyzing crystalline phases and on a minimal scheme for polymer analysis and characterization to assist the design engineer. The article ends with a discussion on the thermal-analytical scheme for analyzing the milligram quantities of polymer samples.

This article addresses some established protocols in characterizing thermoplastics, whether they are homogeneous resins, alloyed or blended compositions, or highly modified thermoplastic composites. It begins with a description of various approaches used for the determination of molecular weight (MW) by viscosity measurements. This is followed by a discussion of the use of cone and plate and parallel plate geometries in determining the viscoelastic properties of a polymer melt. Details on some of the chromatographic techniques that allow determination of MW and MW distribution of polymers are then provided. The article concludes with information on three distinctive, but complementary operations of thermoanalytical techniques, namely differential scanning calorimetry, thermogravimetric analysis, and thermomechanical testing.

This chapter compares and contrasts the high-temperature behaviors of metals and composites. It describes the use of creep curves and stress-rupture testing along with the underlying mechanisms in creep deformation and elevated-temperature fracture. It also discusses creep-life prediction and related design methods and some of the factors involved in high-temperature fatigue, including creep-fatigue interaction and thermomechanical damage.

This article covers the thermal analysis and thermal properties of engineering plastics with respect to chemical composition, chain configuration, and/or conformation of the base polymers. The thermal analysis techniques covered are differential scanning calorimetry, thermogravimetric analysis, thermomechanical analysis, and rheological analysis. The basic thermal properties covered include thermal conductivity, temperature resistance, thermal expansion, specific heat, and the determination of glass-transition temperatures. The article further describes various factors influencing the determination of service temperature of a material. Representative examples of different types of engineering thermoplastics are discussed in terms of structure and thermal properties. The article also discusses the thermal and related properties of thermoset resin systems.

This chapter provides an overview of the nomenclature, generations, and thermomechanical processing of advanced high-strength steels (AHSS) and provides information on the development of microstructure. It also presents a review of the mechanical property trends of AHSS.

This chapter discusses the properties and compositions of steels used in pressure vessels, piping, boilers, rebar, and other structural applications. It covers fine-grained steels, quenched and tempered steels, and controlled rolled (thermomechanical treatment) steels. It also compares and contrasts steels used for concrete reinforcement and in various types of pressure vessels, and presents a metallographic study of the effects of welding on the micro and macrostructure of steel.

Fiber-reinforced metal-matrix composites have carved out a niche in applications requiring high strength to weight ratios, but they are susceptible to failure when exposed to high temperatures and cyclic loads. This chapter discusses the obstacles that must be overcome to improve the creep-fatigue behavior of these otherwise promising materials. It addresses six areas that have been the focus of intense research, including thermal-expansion and elastic-viscoplastic mismatch, thermally induced biaxiality and interply stresses, creep and cyclic relaxation of residual stresses, and enhanced interfaces for oxidation.

This chapter provides practical information on the forming and forging processes used to manufacture titanium parts, including die forging, precision die forging, hot and cold forming, superplastic forming, and deep drawing. It explains how process variables such as temperature, pressure, and strain rate influence microstructure and properties and provides recommended ranges for commonly formed and forged titanium alloys.

This chapter explains why it is sometimes necessary to separate inelastic from elastic strains and how to do it using one of two methods. It first discusses the direct calculation of strain-range components from experimental data associated with large strains. It then explains how the method can be extended to the treatment of very low inelastic strains by adjusting tensile and compressive hold periods and continuous cycling frequencies. The chapter then begins the presentation of the second approach, called the total strain-range method, so named because it combines elastic and inelastic strain into a total strain range. The discussion covers important features, procedures, and correlations as well as the use of models and the steps involved in predicting thermomechanical fatigue (TMF) life. It also includes information on isothermal fatigue, bithermal creep-fatigue testing, and the predictability of the method for TMF cycling.

This chapter discusses the use of finite-element modeling in forging design. It describes key modeling parameters and inputs, mesh generation and computation time, and process modeling outputs such as metal flow, strain rate, loading profiles, and microstructure. It also includes a variety of application examples.

Titanium alloys are classified according to the amount of alpha and beta phase material retained in their structures at room temperature. This chapter discusses the metallurgy, composition, processing, and properties of titanium and its alloys. It provides information on melting, forging, casting, heat treating, and secondary fabrication. It also discusses the advantages and disadvantages of titanium and its alloys in various applications.

This article discusses the effect of alloying on the composition, structure, properties, and processing characteristics of ordered intermetallic compounds, including nickel aluminides, iron aluminides, and titanium aluminides. It includes several data tables along with a list of typical applications.

This article reviews various analytical techniques most commonly used in plastic component failure analysis. The description of the techniques is intended to make the reader familiar with the general principles and benefits of the methodologies. The descriptions of the analytical techniques are supplemented by a series of case studies that include pertinent visual examination results and the corresponding images that aided in the characterization of the failures. The techniques covered include Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, thermomechanical analysis, and dynamic mechanical analysis. The article also discusses various analytical methods used to characterize the molecular weight distribution of a polymeric material. It provides information on a wide range of mechanical tests that are available to evaluate plastics and polymers, covering the various considerations in the selection and use of test methods.

This chapter begins with a description of the requirements of tooling and tooling material for hot extrusion. It covers the processes of designing tool and die sets for direct and indirect extrusion. Next, the chapter provides information on extrusion tooling and die sets for direct external and internal shape production and tools for copper alloy extrusion. Further, it addresses design, calculation, and dimensioning of single-piece and two-part containers and describes induction heating for containers. Information on static- and elastic-based analysis and dimensioning of containers loaded in three dimensions is provided. Examples of calculations for different containers, along with their stresses and dimensions, are presented and the manufacture, operation, and maintenance of containers are described. The chapter further discusses the properties and applications of hot working materials for the manufacture of extrusion tooling and of different extruded materials for the manufacture of extrusion tooling for direct and indirect forming.

Combustion turbines consist of a compressor, a combustor, and a turbine. As commonly configured, the compressor and turbine mount on a single shaft that connects directly to a generator. This chapter reviews the materials of construction, damage mechanisms, and life-assessment techniques for nozzles and buckets. It also presents key information from a detailed review of the literature and the results of a survey on combustion-turbine material problems.

Hot stamping is a forming process for ultrahigh-strength steels (UHSS) that maximizes formability while minimizing springback. This chapter covers several aspects of hot stamping, including the methods used, the effect of process variables, and the role of finite-element analysis in process development and die design. It also discusses heating methods, cooling mechanisms, and the role of coatings in preventing oxidation.