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.

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.

Wavelength-dependent or hyperspectral imaging is a novel nondestructive characterization technique in the field of neutron radiography and computed tomography. A dedicated facility named VENUS is currently being built at Oak Ridge National Laboratory to provide these characterization capabilities for academia, industry, and other national laboratories. This feature article describes the VENUS capabilities for materials science and engineering, provides a quick overview of the modes of access of the facility, and illustrates the nondestructive measurements and interpretation of results.

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 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.

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.

Pure screw dislocations can become helical by absorbing defects such as vacancies and develop attractive interaction with another helical dislocation to form a double helix structure.

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.

A new type of material based on nanoporous copper foams using metallic nanowires as building blocks has promising applications in filtration media, smart masks, and air cleaners.

This article, the second in a two-part series on titanium alloys, examines the effects of microtexture on deformation behavior, slip dislocations, and fatigue properties. Part I, which appeared in the April 2021 issue, described microstructural evolution processes that result in microtexture formation.

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

Vision-based machine learning systems for microstructural characterization and analysis are being successfully used for image classification, semantic and instance segmentation, and object detection, leading to accurate, autonomous, objective, and repeatable results.

This article demonstrates the application of machine learning to the classification and segmentation of bainitic microstructures and compares three approaches for assigning the ground truth: correlative microscopy using EBSD as an additional information source, comparison with images obtained from specially produced reference samples, and unsupervised learning.

Thermal barrier coatings (TBCs) with segmented or cracked microstructures exhibit enhanced thermal cyclic behavior and erosion resistance, along with improved application economics, over conventional TBCs.

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 primer discusses three image-based methods that simplify the analysis of phase composition, porosity, and particle distribution, thus providing additional insight into the microstructure of materials.

This article describes a procedure for optimizing the annealed microstructure of a high Al KAB steel. The main focus is directed toward characterization of microstructural development during annealing of different phases in a nanostructured bainitic steel using high resolution transmission electron microscopy (HRTEM). This entry won the prestigious 2019 Jacquet-Lucas Award for Excellence in Metallography at the International Metallographic Contest held in Portland, Oregon, October 2019.

This excerpt from ASM Handbook, Volume 10: Materials Characterization describes the technique used to determine crystal structure and the arrangement of atoms in a unit cell.

Structural features, spatial locations, and morphological measures not readily attainable with 2D methods are now accessible using 3D microstructure characterization techniques.