Search Results for microscopy

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 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.

Using a Fourier transform infra red (FTIR) microscope along with an FTIR spectrophotometer proves beneficial in analyzing the complex layers of some composite polymer films. The study reported in this article demonstrates that analysis of the FTIR spectra can help clarify and explain the formulation of different layers that compose the polymer film.

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 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.

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.

Development of new, radiation-tolerant materials that maintain the structural integrity and safety margins over the course of a nuclear power reactor’s service life requires the ability to predict degradation phenomena. Modern post-irradiation examination methods make use of specialized high-flux test reactors and dedicated characterization facilities to limit occupational exposure and prevent the spread of radioactive contamination. This article illustrates the use of these advanced techniques to characterize precipitates in neutron-irradiated Fe-Cr-Al alloys.

In cold spray characterization, scanning electron microscopy is used to analyze feedstock powders for particle size, distribution, shape, and chemical composition prior to spraying. SEM is used extensively to characterize coating chemistry via energy-dispersive x-ray spectroscopy (EDS). Coating thickness and interface contour can be characterized in a manner that makes SEM an indispensable and versatile tool for evaluating coating integrity in the as-sprayed condition, as well as in developing an understanding of bonding to the substrate.

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.

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.

This study presents a comprehensive scale-bridging characterization approach to investigate acicular ferrite nucleation in electron beam welded S355 ML steel, demonstrating the critical role of titanium oxide particles in promoting fracture-resistant microstructures for offshore wind monopile applications. Using a multi-technique methodology spanning light microscopy, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and transmission Kikuchi diffraction (TKD), the researchers identified and analyzed particles that serve as nucleation sites for acicular ferrite formation. This entry won the prestigious 2024 Jacquet-Lucas Award for Excellence in Metallography at the International Metallographic Contest held during IMAT in Cleveland, October 2024.

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.

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.

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.

Forensic metallurgy investigations in archaeology and aerospace engineering follow similar technical protocols but serve different objectives. Archaeometallurgical analyses focus on artifact provenance and cultural heritage management with minimal invasive sampling, while aerospace investigations prioritize rapid failure analysis for operational problems. Four case studies illustrate the approaches: noninvasive macrophotographic analysis of an ancient silver cup revealed stress corrosion cracking, noninvasive investigation of a Boeing 747 accident identified fatigue failure in fuse pins due to inadequate load knowledge, invasive lead isotope analysis successfully provenanced Chinese bronzes using kernel density methods, and comprehensive testing of F-16 wing bolts ruled out hydrogen embrittlement. Both fields employ similar analytical techniques, including microscopy, fractography, and chemical analysis, but differ in sampling constraints, time pressures, and reporting goals, with successful investigations in both domains requiring interdisciplinary teamwork.

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.

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.

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.

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