Optical or light microscopy uses the visible or near-visible portion of the electromagnetic spectrum and is one of the oldest characterization techniques. With any cold spray coating, it is the first characterization process used to evaluate and optimize process variables.

3D laser microscopy is opening new areas of study for metallic alloys and coatings in power generation applications. This article describes some case studies where laser microscopy has augmented, and in some cases replaced, metallic alloy characterization using optical microscopy or scanning electron microscopy.

This article reports on a study to better understand the integrity and microstructure of extrusion welding in a magnesium alloy (AM30) hollow section extrudate using light optical microscopy. The article is based on the entry that won the prestigious Jacquet-Lucas Award for Best in Show at the 2013 International Metallographic Contest.

This new article series explores the indispensable role of characterization in the development of cold spray coatings and illustrates some of the common processes used during coatings development. This article provides a list of techniques to be covered in subsequent articles.

Determining the root cause of avionics failures requires a disciplined and systematic analytical process supported by sophisticated equipment. This article reviews some of the analytical tools and techniques used to understand and prevent avionics failures.

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.

This article reports on development of a versatile new technique that fills the need for grain etching in multiple aluminum alloy series. The procedure is a two-step etch that combines an attack etchant with a stain etchant to reveal grain structure of 2000, 5000, 6000, and 7000 series aluminum alloys. This entry won the prestigious DuBose-Crouse Award for unique, unusual, and new techniques in microscopy at the 2022 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.

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.

The ability to produce bulk metallic nanolaminates has greatly expanded the potential structural applications for these materials, motivating investigations into formability, joining techniques, and deformation behavior. This article presents an overview of both the accumulative roll bonding process and the deformation behavior for copper-niobium nanolaminates. This entry won the Jacquet-Lucas Award for Best in Show at the 2014 International Metallographic Contest.

This article describes the development of applications of phosphate-based materials and characterizes five non-apatite phosphate minerals using 3D optical profilometry. The results reveal the suitability of these materials for new uses in energy storage and conversion as well as medical applications.

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 describes a planned three-year research project at the Center for Heat Treating Excellence (CHTE) at Worcester Polytechnic Institute (WPI) to help the heat treat industry better understand process parameters related to austempering of steels. This research will enable the industry to identify the potential strength, toughness, and cost benefits of bainitic steels over martensitic steels and provide guidance on the design, validation, and control of heat treating processes to produce bainitic microstructures in steels.

A multicomponent thermal spray coating system resists pick-up of contaminants that can cause flaws on heat treated strip surface.

Advances in software algorithms and design enable automation of microstructure image analysis, leading to cost savings, reduction in measurement variability, and access to important metrics.

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

Newly developed nickel-titanium (NiTi) alloys are well suited for bearings and gears in demanding applications.

X-ray microscopy (XRM) offers long working distances and switchable magnification, facilitating time-resolved volumetric investigation of materials and structures. Examples show how XRM opens new windows into microstructure evolution processes in functional materials such as batteries, in response to charge state, and polymer foams, in response to compression loading.

A mixed-reality application called HoloMicroscope helps microscopists make decisions and analyze data efficiently while using transmission electron microscopes. In the context of materials research, using mixed reality augments a user’s interaction by allowing them to see a TEM column and its control panels, while also interacting with three-dimensional holograms that are projected into their field of view. Introduction of mixed reality into a data-intensive research workflow could help accelerate scientific discovery. This article provides background about technology and a case study in its use.

In this study, 316L stainless steel samples were plasma nitrided for 64 h at 370-420 °C then subjected to surface hardness and pitting corrosion testing. The results show that interstitial hardening with nitrogen significantly improved the surface hardness as well as the pitting corrosion resistance of the austenitic stainless steel.