Laser powder bed fusion (LBFP) additive manufacturing is a potential route for the rapid qualification of new materials for use in nuclear reactor design. Process anomalies such as spatter particles can induce lack of fusion (LOF) voids that may adversely affect the material's mechanical performance. This examination of the spatter particle process in a nickel superalloy using X-ray computed tomography and optical microscopy was conducted to identify possible causes for the formation of LOF voids and other variations during LBPF processing.

As high-entropy alloys become more complex in terms of microstructure, phase stability, and intermetallics, the advent of sophisticated analytical instruments is helping scientists to develop new materials with the most desirable properties. The analysis techniques described in this article include electron energy loss spectroscopy, electron probe microanalysis, atom probe tomography, and x-ray absorption spectroscopy.

This article summarizes the more common analytical techniques for studying ancient metal artifacts, illustrated by case histories. There are two main classifications: noninvasive and invasive techniques. This distinction is of prime importance because some heritage objects may be too rare or valuable for invasive sampling, or there may be ethical objections to certain types of examination. Noninvasive examination of ancient metal artifacts is important, yet it cannot provide the detailed information obtainable from invasive techniques. This is especially true when artifacts contain “hidden” damage and there is also a need for accurate quantitative analyses.

Wire arc directed energy deposition (WDED) is a robust alternative for large-scale metal printing. It offers high deposition rates, excellent material and energy efficiency, and reduced waste material compared to conventional manufacturing processes. This article describes a study that employed a combination of standard and advanced characterization techniques to assess the mechanical behavior of WDED titanium samples. This entry won first place in the light microscopy category of the prestigious 2023 International Metallographic Contest.

This article reviews the analytical techniques used for phase identification in components, including x-ray diffraction, metallography/microscopy, electron backscatter diffraction, trasmission electron microscopy,and atom probe tomography. The article addresses the advantages and disadvantages of each technique compared to the other approaches.

Atomic force microscopy studies show that sharp yield points in steels are explained by the existence of hard grain boundary walls, contrary to current accepted theories.

This article describes sample preparation to create a visually impressive micrograph image of single-phase cartridge brass, C26000, an alloy composition of 70% copper and 30% zinc. C26000 was chosen due to the striking twins and large grain size that are easily generated by annealing a cold-worked sample, the large range of contrast and colors that can be created by etching, and the wide availability of the material. This entry won the Jacquet-Lucas Award for Best in Show at the 2021 International Metallographic Contest.

Two case studies highlight the strengths and weaknesses between traditional metallurgical techniques and 3D micro-computed tomography, as well as the interplay between the two.

In steel production, an automated particle workflow can increase the efficiency and statistical relevance of nanosized precipitate analyses, resulting in increased productivity and accuracy.

A microscope using differential interference contrast inspects grains and inclusions on heat treated aluminum parts to help predict the performance of the metal.

Using advanced characterization techniques on surface hardened steels builds a richer understanding of the underlying metallurgical phenomena.

This entry won the prestigious Jacquet-Lucas Award for Best in Show in the 2020 International Metallographic Contest. In the research discussed in this article, light microscopy was applied to a Co28Cr6Mo alloy for a biomedical application processed by laser bed powder fusion (LPBF) additive manufacturing.

This article explains how SEM, TEM, and atom probe tomography are being used in the development of additively manufactured high-entropy alloys (HEAs), revealing critical features such as anisotropic microstructure and metallurgical defects. It also discusses ongoing efforts to improve the predictability and analysis of HEA microstructure using data-driven approaches.

New electrical, mechanical, and chemical testing capabilities give scanning electron microscopes the feel of a self-contained “nano-laboratory.” Several developments in SEM technology allow new and more flexible approaches to the analysis of novel systems, such as Li battery-related materials, nanostructured and nanoporous materials, and novel approaches to 3D analysis.

Integrated elemental analysis with color imaging lets researchers quickly and accurately answer compositional questions.

Many broken parts look similar at a glance, but examination of the failed part using advanced equipment and methods such as scanning electron microscopy (SEM) reveals much more about the origins of the failure. This article presents a case history involving SEM analysis of a trailer hitch fatigue failure.

Characterizing ice and snow is important not only for building accurate climate models, but also for activities such as relating the mechanical properties of sea ice to its microstructure so that the interaction of ice with ships and structures can be better understood. This article describes the microstructural characterization of ice. Many microstructural characterization techniques that can be applied to other materials also can be used to examine ice.

This article series explores the indispensable role of characterization in the development of cold spray coatings. Transmission electron microscopy is used to understand powder characteristics, cold spray coating deformation behavior both within splats as well as near the coating-substrate interface, phase transformations in the as-sprayed and heat treated conditions, phase equilibria of the coating under the operating conditions pertaining to the application of the coating, the coating recovery mechanism, and the thermal stability of the coating.

Focused ion beam (FIB) systems are selectively used in cold spray coating characterization to gather information on the nature of splat formation, single splats, multiple splats, or the coating-substrate interface. Electron probe microanalysis has been used in cold-sprayed coating characterization primarily to understand the bonding mechanism at the coating-substrate interface.

Scanning electron microscopy and energy dispersive x-ray spectroscopy open new windows into glassmaking processes.