Both surface finish and surface integrity must be defined, measured, and maintained within specified limits in the processing of any product. Surface texture is defined in terms of roughness, waviness, lay, and flaws. This article illustrates some of the designations of surface roughness and the symbols for defining lay and its direction. In addition, it describes the applications of surface integrity, typical surface integrity problems created in metal removal operations, and principal causes of surface alterations produced by machining processes. The article tabulates the effect of some machining methods on fatigue strength, and low-stress grinding procedures for steels, nickel-base high-temperature alloys, and titanium alloys.

Most surfaces have regular and irregular spacings that tend to form a pattern or texture on the surface. This article provides information on the general background of surface topography and discusses the different methods for measuring surface topography, namely, contact and noncontact techniques, and the focus-follow method. Examples of different types of parameters obtained and how they are applied can best be described by discussing the various types of surfaces generated by finishing methods. The surfaces include ground, turned, and milled machined surfaces; surfaces subjected to stress; bearing surfaces; plateau honed and tapped surfaces; and reflective, painted, elastic, and wear-resistant surfaces.

This article focuses on the various technology drivers for finishing methods, namely, tolerance, consistency, surface quality, and productivity. Every finishing method may be viewed as a manufacturing system consisting of four input categories: machine tool, processing tool, work material, and operational factors. The article provides a classification of finishing as a surface generation process and addresses the characteristics of the generated surfaces and the methods used to measure them. It describes the thermomechanical interactions occurring between the processing tool and the work material in the presence of machine tool and operational factors.

This article describes the mechanism, advantages and disadvantages, fundamentals, capabilities, variations, equipment used, and weldability of metals in solid-state welding processes, including diffusion bonding, explosion welding, friction welding, ultrasonic welding, upset welding, and deformation welding.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of pure irons and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the grain-boundary cavitation; slip lines; intergranular fracture; cleavage fracture; notch-impact fracture; oxide inclusions and blowholes; ductile rupture; impact fracture and tensile-test fracture surfaces; fatigue striations; and crack initiation and propagation of pure irons.

This article is an atlas of fractographs that covers pearlitic and ferritic ductile irons. The fractographs display the following: brittle cleavage fracture; fatigue crack propagation; fatigue and monotonic fracture surfaces; fracture modes in slow monotonic loading and impact loading; and microcrack initiation and propagation.

The compression molding process is most commonly called the sheet molding compound (SMC) process in reference to the precursor sheet molding compound material it uses. This article discusses the types of materials used for sheet manufacture, and describes the manufacturing and processing parameters of SMC components, providing details on tooling and process advantages and limitations. The article provides a general overview of the types of compression molding processes, including structural compression molding and thermoplastic compression molding.

The concept of surface integrity for grinding operations can be extended to encompass six different groups of key factors: visual, dimensional, residual stress, tribological, metallurgical, and others. This article discusses the importance of these factors in the performance and behavior of finishing methods in various manufactured parts. Special emphasis is given to residual stresses and their influence on the final mechanical properties of a manufactured part.

Visual examination, using the unaided eye or a low-power optical magnifier, is typically one of the first steps in a failure investigation. This article presents the guidelines for selecting samples for scanning electron microscope examination and optical metallography and for cleaning fracture surfaces. It discusses damage characterization of metals, covering various factors that influence the damage, namely stress, aggressive environment, temperature, and discontinuities.

Plastic deformation can occur in metals from various mechanisms, such as slip, twinning, diffusion creep, grain-boundary sliding, grain rotation, and deformation-induced phase transformations. This article emphasizes on the mechanism of slip and twinning under cold working conditions. It discusses the factors on which the structures developed during plastic deformation depend. These factors include crystal structure, amount of deformation, composition, deformation mode, and deformation temperature and rate. The article illustrates the microstructural features that appear after substantial deformation when revealed through metallographic investigation.

One impressive example of plane front solidification (PFS) is the industrial production of large silicon single crystals, used mainly as substrates for integrated circuits. This article explores the PFS of a single phase, without taking convection into account. It discusses the solute build-up at the solid-liquid interface forming transients and steady state, the morphological stability/instability and perturbation theory, and rapid solidification effects, including solute trapping and oscillatory instabilities. The article presents a microstructural selection map that gives an overview of interface stability as a function of composition for a given alloy.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of titanium alloys and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the fracture surface, fatigue crack growth, intergranular fracture, crack propagation, ductile overload fracture, dimpled rupture, microvoid coalescence, and quasi-cleavage fracture of these alloys.

This article briefly introduces the concepts of failure analysis, including root-cause analysis (RCA), and the role of failure analysis as a general engineering tool for enhancing product quality and failure prevention. It initially provides definitions of failure on several different levels, followed by a discussion on the role of failure analysis and the appreciation of quality assurance and user expectations. Systematic analysis of equipment failures reveals physical root causes that fall into one of four fundamental categories: design, manufacturing/installation, service, and material, which are discussed in the following sections along with examples. The tools available for failure analysis are then covered. Further, the article describes the categories of mode of failure: distortion or undesired deformation, fracture, corrosion, and wear. It provides information on the processes involved in RCA and the charting methods that may be useful in RCA and ends with a description of various factors associated with failure prevention.

This article considers the two primary methods used for ultrasonic inspection: pulse-echo and the transmission methods. Pulse-echo inspection can be accomplished with longitudinal, shear, surface (Rayleigh), or Lamb (plate) waves using a diverse range of transducers. The article discusses the principles of each of these inspection methods. It describes the applications and the basic data formats for single-element transducer-based systems, including A-scans, B-scans, and C-scans. The article provides information on electronic equipment used for ultrasonic inspection. It also describes how specific material conditions produce and modify A-scan indications. The article provides information on the controls and their functions for the display unit of the electronic equipment. It describes the techniques used for the identification and characterization of flaws, namely, surface (Rayleigh) wave and ultrasonic polar scan techniques.

This article introduces the principal methodologies and some advanced technologies that are being applied for nondestructive evaluation (NDE) of fiber-reinforced polymer-matrix composites. These include acoustic emission, ultrasonic, eddy-current, computed tomography, electromagnetic acoustic transducer, radiography, thermography, and low-frequency vibration methods. The article also provides information on NDE methods commonly used for metal-matrix composites.

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.

This article describes the use of conventional machining techniques, laser cutting and water-jet cutting for producing finished composite parts. It explains two representative polymer-matrix composites--graphite and aramid composites--and discusses the machining and drilling problems such as delamination and fiber or resin pullout. The article describes machining and drilling techniques and the necessary tools and cutting parameters. It presents a description of laser cutting. The article also provides information on the advantages, disadvantages, cutting characteristics, and applications of water-jet cutting and abrasive water-jet cutting.

Computed tomography (CT) is an imaging technique that generates a three-dimensional (3-D) volumetric image of a test piece. This article illustrates the basic principles of CT and provides information on the types, applications, and capabilities of CT systems. A comparison of performance characteristics for film radiography, real-time radiography, and X-ray computed tomography is presented in a table. A functional block diagram of a typical computed tomography system is provided. The article discusses CT scanning geometry that is used to acquire the necessary transmission data. It also provides information on digital radiography, image processing and analysis, dual-energy imaging, and partial angle imaging, of a CT system.

Engineering component and structure failures manifest through many mechanisms but are most often associated with fracture in one or more forms. This article introduces the subject of fractography and aspects of how it is used in failure analysis. The basic types of fracture processes (ductile, brittle, fatigue, and creep) are described briefly, principally in terms of fracture appearances. A description of the surface, structure, and behavior of each fracture process is also included. The article provides a framework from which a prospective analyst can begin to study the fracture of a component of interest in a failure investigation. Details on the mechanisms of deformation, brittle transgranular fracture, intergranular fracture, fatigue fracture, and environmentally affected fracture are also provided.

This article reviews the failure analysis process with specific reference to the considerations that should be addressed when a casting has failed. It describes the failure analysis methodology for three failed cast components: an aluminum bracket, a bronze suction roll, and a steel automotive spindle. The article discusses failure analysis investigation by obtaining casting background information, planning the evaluation and selecting the appropriate casting for analysis, conducting a preliminary examination, conducting the proper material evaluations, and thoroughly evaluating the test data. It concludes with information on case studies that show how the methodology is adapted for differing materials, failure mechanisms, and failure circumstances.