Search Results for bronze

This article concludes a two-part series on the bronze cymbal-making process as performed by ancient metalworkers and modern cymbalsmiths. The manufacturing process and cymbal metallurgy are described and examined through historical context and technological advances incorporated in the modern age. Part I, which appeared in the May/June 2024 issue, described the first steps in the art of cymbal making.

The initial steps in the art of manufacturing cymbals are discussed from ancient times through the modern era, including copper smelting, alloying copper and tin, pouring the molten metal into ingots, and processing the ingots by hand-hammering or rolling a finished blank.

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.

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.

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.

The production and processing of advanced materials, namely metals and alloys, began in the Old World about 8000 years ago and developed over many millennia, providing a lasting legacy for modern civilizations. This article gives a brief overview of the production and processing of ancient bronzes and silver in the Old World, and also mentions post-processing problems including corrosion and embrittlement, owing to long-term burial before archaeological recovery.

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.

Optimizing the integrity and performance of highly engineered surfaces and structures requires the ability to visualize and understand material behavior over multiple length and time scales from a three-dimensional perspective. The Electron Microscopy Centre at the University of Manchester is equipped for such work as demonstrated in problem-solving scenarios involving multiscale imaging and analysis of the progression of intergranular corrosion in Al alloy 2024, the catalytic effect of silver nanoparticles in seawater, recrystallization in a volume element of a bronze alloy, and defect progression on graphene surfaces.

Laboratory tests conducted at the University of Southampton, UK, found that many species of bacteria including hospital superbugs, MRSA and VRE, are killed in less than 2 h on copper alloy surfaces. Tests conducted in a third-party lab subject to EPA audits confirmed these results, concluding that a range of copper alloy surfaces, such as brass, bronze, copper nickel, and nickel silver, achieve a 99.9% reduction of bacteria within 2 h of contact and that the effect is not impaired by tarnish. Other such tests have since been conducted and the results are presented in the article.

A brief literature review and case study explore the effect of particulate reinforcements and processing parameters on the tribological behavior of polymer matrix composites made by 3D printing via fused filament fabrication.

A look at processing and production of iron during the Iron Age, 1200 to 500 B.C., including early unintentional forms of steel.

A world-renowned archaeometallurgist reflects on his career within the discipline and the technological advancements he witnessed during five decades out in the field and at the microscope.

News about ASM members, chapters, events, awards, conferences, affiliates, and other society activities. Topics include: Affiliate societies name committee chairs for 2014-2015 term; ASM appoints Terry Mosier as interim managing director.

This case study details the noninvasive analysis of an 5000-year-old silver figurine from Iran, now in the collection of The Metropolitan Museum of Art. The The object of this study, a figure of a kneeling bull clothed in a robe with a stepped linear pattern and holding up a spouted vessel, is composed of 15 pieces of worked silver joined together with silver solder. The aim of the study is to apply noninvasive micro-xray fluorescence spectroscopy (μ-XRF) analysis to characterize the silver alloy compositions and compare the new data with previously obtained results from invasive chemical analyses of samples performed by thermal neutron activation.

This article describes a metallographic and SEM study of a Spanish silver coin. The study verified the coin's authenticity and determined its alloy composition. The investigation is an example of a unique archaeometallurgical collaboration between a university and a museum.

A look at Monel after decades of exposure to the environment shows more work is needed to address the lack of scientific research and information in the conservation literature. Three case studies are presented related to the analysis of Monel artifacts.

A study of metal artifacts from the Mendoza region of Argentina reveals the influences of native migration and European conquest.

News about ASM members, chapters, events, awards, conferences, affiliates, and other society activities. Topics include: Appointment of 2021-2022 ASM Committee and Council chairs; ASM's new Executive Director, Sandy Robert; contributor spotlight for Roch J. Shipley.

This article provides a brief overview of the applications of multimodal alumina-titania (n-AT) coatings stemming from a five-year program on thermal spray nanocoatings sponsored by the U.S. Office of Naval Research (ONR). In the main example, plasma sprayed n-AT coatings are applied to the propulsion shafts of Mine Countermeasure ships, bringing a fourfold increase in service life.

News about ASM members, chapters, events, awards, conferences, affiliates, and other society activities. Topics include: ASM affiliate societies announce officers and board members for 2015; highlights from MS&T 2015 held in Columbus, Ohio; volunteer profile for Nate Eisinger.