This chapter instructs the metallographer on the basic skills required to prepare a polished metallographic specimen. It is organized in a chronological sequence starting with the information-gathering process on the material being investigated, then moving on to sectioning, mounting, grinding, and polishing processes, and ending with methods used to properly store metallographic specimens. The discussion covers the preparation procedures, the materials being investigated, and equipment used to perform these procedures.

This chapter discusses the important role of metallography and the metallographer in predicting and understanding the properties of metals and alloys. Examples are presented of a metallographer working as part of a team in a research laboratory of a large steel company and a metallographer working alone at a small iron foundry. The three basic areas in all metallography laboratories are discussed: the specimen preparation area, the polishing/etching area, and the observation/micrography area. Important safety issues in a metallographic laboratory are also considered.

Molybdenum thermal spray coatings are used in aerospace and other industries for wear resistance applications. Metallographic sample preparation of molybdenum coatings presents unique challenges. The purpose of the investigation described in this article is to determine Accepted Practices for sample preparation to better understand the process related microstructures of thermal spray molybdenum powders. The committee followed a round robin approach to assess metallographic sample preparation by a variety of laboratories. The article summarizes the results of the committee’s work.

Thermal barrier coatings (TBCs) are applied using thermal spray coating (TSC) processes to components that are internally cooled and operated in a heated environment. The TSC microstructures are prone to interactions with common metallographic procedures that may result in artifacts and misinterpretation of the TSC microstructure. This article aims to aid in identifying metallographic TSC artifacts, specifically in the air plasma spray zirconia-based TBC, including both of its common constituents, the bond coating and the top coating. Artifacts that result from specific sectioning and mounting practices, as well as from different polishing times, are presented. Additionally, the article discusses the factors in optical microscopy and scanning electron microscopy that affect microstructure interpretation.

This chapter explains how to prepare metallographic samples for light microscopy and how to anticipate and avoid related problems. It describes standard practices and procedures for sectioning, mounting, grinding, and polishing and identifies common defects along with their causes and cures. It also provides recommendations for handling specific materials and addresses safety concerns.

This article presents best practices for the metallographic preparation of specimens produced via thermal spray coating methods. It outlines typical metallographic preparation process flow, highlighting important considerations for obtaining a clear and representative specimen suitable for characterization via examination techniques, such as optical or electron microscopy. The process flow includes preliminary resin infiltration, sectioning, mounting, grinding, and polishing. To aid in the identification and resolution of common issues during subsequent specimen analysis, the article presents common issues, along with causes and mitigation strategies. It describes the processes involved in the interpretation of the thermal spray coating microstructure.

This chapter explains how to prepare material samples for optical microscopy, the most common method for characterizing the microstructure of cast iron and steel. It provides information on sectioning, mounting, polishing, etching, and recording. It describes the nature of surface roughness, the factors that contribute to it, and its effect on image quality. It discusses the use of fixturing and holding devices, includes photographic examples of polishing defects and drying marks, and provides an overview of micrographic etchants and the features they reveal. It also describes the steps involved in replicating part surfaces.

This chapter explains how to safely prepare beryllium alloy samples for metallographic analysis. It describes grinding, polishing, and etching procedures in detail. It also discusses the identification of major and minor constituents and the general appearance of beryllium microstructure.

This chapter describes the methods and equipment applicable to metallographic studies and discusses the preparation of specimens for examination by light optical microscopy. Five major operations for preparation of metallographic specimens are discussed: sectioning, mounting, grinding, polishing, and etching. The discussion covers their basic principles, advantages, types, and applications, as well as the equipment setup. The chapter includes tables that list etchants used for microscopic examination. It also provides information on microscopic examination, microphotography, and the effects of grain size on the structural properties of the material.

This chapter discusses the practices and procedures used to reveal and record macrostructural features such as hardening depth, weld thickness, crack size, porosity, hot folds, and machining and tooling marks. It provides information on sectioning, sample location, orientation, surface grinding, and etching. It describes macrographic etchants and the features they reveal along with common etching problems and how to avoid them. It explains how to evaluate etching results and how they can be improved using remedial processes such as light grinding. It also discusses photographic reproduction, lighting, and image enhancement techniques.

Cross-sectioning is a technique used for process development and reverse engineering. This article introduces novice analysts to the methods of cross-sectioning semiconductor devices and provides a refresher for the more experienced analysts. Topics covered include encapsulated (potted) device sectioning techniques, non-encapsulated device techniques, utilization of the focused ion beam (FIB) making a cross-section and/or enhancing a physically polished one. Delineation methods for revealing structures are also discussed. These can be chemical etchants, chemo-mechanical polishing, and ion milling, either in the FIB or in a dedicated ion mill.

Abradable coatings (such as Ni-4Cr-4Al/bentonite) are used throughout jet engines, primarily as sacrificial coatings into which moving components wear. This article presents the Accepted Practice for sample preparation of abradable coatings for metallographic analysis, based on round robin testing by several laboratories.

Examining and evaluating the nitrided case is generally accomplished by hardness testing and microscopic examination. This chapter discusses both characterization methods, as well as sample preparation. The chapter also discusses the processes involved in the etching of the sample after microhardness testing and provides practices that contribute to the safe preparation of specimens. Examples of nitrided case microstructures, using optical light microscopy, are also presented.

Mechanical treatments such as grinding and shot peening are often employed in the production of case-carburized parts. Grinding, besides restoring precision, removes carbide films, internal oxidation, and high-temperature transformation products. Shot peening strengthens component surfaces and induces a stress state that increases fatigue resistance. This chapter describes both processes as well as roller burnishing. It explains how these treatments are applied and how they influence the microstructure, properties, and behaviors of case-hardened components. It also addresses process challenges, particularly in regard to grinding.

This chapter describes several macroscopic examination techniques, including macroetching, contact printing, fracturing, and lead exudation. It explains how each method is implemented, why it is used, and what it reveals about manufacturing processes, defects, imperfections, and failure mechanisms.

The practical application of metals and alloys is guided largely by information obtained through the study of their microstructure. This chapter examines a wide range of titanium microstructures, identifying characteristic features and explaining what they reveal about processing, properties, and performance. It includes images of elongated and equiaxed structures, primary alpha, transformed beta, and metastable phases as well as spheroidal and intergranular beta, alpha case, and intermetallic compounds. It also defines important terms and provides step-by-step procedures for preparing titanium for metallographic analysis.

This chapter presents definitions of terms related to the metallurgy and metallographic study of irons and steels.

This chapter reviews weld corrosion in three key application areas: petroleum refining and petrochemical operations, boiling water reactor piping systems, and components used in pulp and paper plants. The discussion of each area addresses general design and service characteristics, types of weld corrosion issues, and prevention or mitigation strategies.