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.

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.

Although stress corrosion cracking (SCC) accounts for just a fraction of all engineering failures, its prevention is a major problem, particularly in the aerospace industry. Recent archaeometallurgical studies show that stress corrosion cracking occurred in ancient metallic artifacts. This article describes investigations that revealed definite evidence for SCC in ancient silver and bronze alloys and a probable case of SCC in low-carat (13K) gold. Diagnostic methods included visual inspection, metallography, and fractography.

Selecting materials for high-pressure hydrogen systems requires balancing technical understanding of hydrogen embrittlement and business considerations. While the direct effect of hydrogen on materials is usually manifested as ductility loss under tension stress, the most concerning failure in a hydrogen system is fatigue. Although no material is immune to property degradation caused by hydrogen, Type 316 stainless steel is among the best in resisting hydrogen embrittlement.

An advanced, patented probe sensor provides early detection of water infrastructure problems caused by corrosion and harsh atmospheric conditions. Designed to detect graphitization in active pipelines, it identifies areas at risk of major failures early on. By using indirect methods like GIS mapping, in-situ soil resistivity testing, and structure-to-soil potential measurements, high-risk zones can be pinpointed. Once these areas are identified, the probe assesses the severity and depth of graphitization, providing a comprehensive evaluation of the pipeline’s condition. This allows for the implementation of effective corrosion management strategies, including cathodic protection systems, to prevent critical failures. This article describes the sensor system and provides a case study of its use. The technology received the 2024 Engineering Materials Achievement Award from ASM International.

Stress corrosion cracking is an insidious form of damage that can occur when a susceptible metal is subjected to a tensile stress in a specific environment. To relieve tensile stresses at welded joints, postweld heat treatment can be helpful in reducing the susceptibility of carbon steel fabrications to SCC. When planning to use stainless steels in chloride-containing environments, it is advisable to select alloys that have been specifically developed to resist stress chloride cracking such as ferritic-austenitic (duplex) alloys, low-carbon ferritic alloys, and 6% Mo austenitic alloys or to select high-nickel alloys.

A new ISO standard could help spur development of new surface treatments and innovative products that can help defend against harmful bacteria and biofilms. This article describes the successful development and adoption of a new standard, ISO 4768:2023, that addresses measurement of anti-biofilm activity on plastic and other nonporous surfaces.

This article explores one of the most commonly used analytical techniques in plastic component failure analysis—Fourier transform infrared spectroscopy—along with a case study to demonstrate its use.

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.

Additive manufacturing techniques give the mining industry a chance to revolutionize the conceptualization, prototyping, and production of mining tools, including using WC-Fe, Ni-based matrix coatings that display exceptional properties. The article includes a case study involving the successful utilization of WC-NiCrBSi mixed powder as a protective coating on AISI 9310 steel components to enhance wear resistance and durability for mining tool applications.

This article reports on a multifaceted testing and modeling approach to investigate the fatigue life of medical grade Nitinol to one billion cycles. The goal of a the research is to understand the mechanism of Nitinol ultra-high cycle fatigue and to eventually be able to predict when fracture will occur.

An examination of a bearing failure due to mismatched and incomplete flame hardening shows the need to work with heat treaters for proper selection and application. The article includes a case study of a large bearing raceway that failed due to incomplete austenitization.

Fire risk in electric vehicle batteries can be reduced by detecting flaws through nondestructive visualization. Industrial computed tomography (CT scanning) combined with advanced software that makes sense of CT-generated images, allows users to measure voids and particle sizes within electrode active material during the research and development phase, detect delamination and contamination during cell manufacturing, analyze electrical connections and electrolyte fill levels, and provide many other quality-assurance functions that were once impractical or even impossible to perform.

This article provides an overview of cracking and fracture mechanisms in heritage gold, silver, low-tin bronze, and wrought iron alloys. Understanding these mechanisms can be important for restorers, and possibly for conservators and curators as well. Metallography is widely used (when sampling is permitted) for studying archaeometallurgical artifacts in detail. However, fracture surface examinations and analysis (i.e., fractography) can often provide even greater insight. Case studies demonstrate the benefits of employing fractographic analysis to study cracking and fracture mechanisms in heritage alloys.

Phase coherence imaging is a new approach for processing ultrasonic signals generated during nondestructive testing. This article shows how it compares with amplitude-based focusing methods for detecting hydrogen-related microfissures, creep-induced damage, and stainless-steel weld voids.

A look at how bifilms are created during casting may offer clues to eliminating cracks, tensile fracture, fatigue failure, pitting, and stress corrosion cracking failures.

Examining a failed part’s fracture surface is a great source of information as to why and how it failed.

Developing a disciplined approach to standardizing special processes and introducing new technologies is key to eliminating defects in thermal spray applications.

The second article in this series looks at materials testing, microstructural evaluation, mechanical testing, and residual stress and distortion using the DANTE Controlled Gas Quenching process.

This study looks at whether adding an annealing step to the heat treating process has an effect on residual stress and distortion on hypoid gear sets. Test results indicate that the annealing heat treatment introduced between gear set soft cutting and case carburizing helped to minimize distortion.