Martha Goodway

Precipitation Hardening in the First Aerospace Aluminum Alloy: The Wright Flyer Crankcase

Aluminum has had an essential part in aerospace history from its very inception: An aluminum copper alloy (with a copper composition of 8 percent by weight) was used in the engine that powered the historic first flight of the Wright brothers in 1903. Examination of this alloy shows that it is precipitation-hardened by Guinier-Preston zones in a bimodal distribution, with larger zones (10 to 22 nanometers) originating in the casting practice and finer ones (3 nanometers) resulting from ambient aging over the last 90 years. The precipitation hardening in the Wright Flyer crankcase occurred earlier than the experiments of Wilm in 1909, when such hardening was first discovered, and predates the accepted first aerospace application of precipitation-hardened aluminum in 1910.

Kestel: An Early Bronze Age Source of Tin Ore in the Taurus Mountains, Turkey

An ancient mine located at Kestel on the outskirts of Nigde, in the Taurus Mountains of south central Turkey, has been dated by radiocarbon and pottery type to the third millennium B.C. Archeological soundings in the mine located cassiterite (tin oxide) in the detritus of ancient mining activity. Cassiterite is also present in veins and, as placer deposits, in streams nearby. Since tin is used with copper in order to form bronze but is thinly distributed in the earths crust, the presence of tin ore at Kestel offers a source for the much sought after tin of the Bronze Age. The discovery of an ancient mine containing cassiterite sheds light on this question, but also greatly complicates the accepted picture of regional economic patterns in the highland resource areas of Anatolia and of interregional metal exchange in the formative periods of urbanization and metal use in the eastern Mediterranean.

Fiber Identification in Practice

AbstractBrief case studies of the problems in identification of a wide variety of ethnographic and archaeological fibers are given. The strategy of identification varied with the purpose (choice of treatment, assessment of damage or identification of its cause, or authentication) but most of all with the condition of the fibers. Fibers from ethnographic or archaeological sources tend to be aged, and are sometimes fragmentary or decayed, fossilized or charred. With fibers in such condition, the simpler methods of preparation for microscopic observation were found more successful than the classical biological methods of soaking, clearing and staining.Not all fibers could be identified. Fur fibers from characteristic areas of the pelt were usually diagnostic as to species as well as to genus. Vegetable fibers were often not mophologically specific to species. Unless “guide elements” were present, or special limitations on species distribution were known, the identification of the genus of a vegetable fiber w...

Phosphorus in Antique Iron Music Wire

Harpsichords and other wire-strung musical instruments were made with longer strings about the beginning of the 17th century. This change required stronger music wire. Although these changes coincided with the introduction of the first mass-produced steel (iron alloyed with carbon), carbon was not found in samples of antique iron harpsichord wire. The wire contained an amount of phosphorus sufficient to have impeded its conversion to steel, and may have been drawn from iron rejected for this purpose. The method used to select pig iron for wire drawing ensured the highest possible phosphorus content at a time when its presence in iron was unsuspected. Phosphorus as an alloying element has had the reputation for making steel brittle when worked cold. Nevertheless, in replicating the antique wire, it was found that lowcarbon iron that contained 0.16 percent phosphorus was easily drawn to appropriate gauges and strengths for restringing antique harpsichords.

Archaeometallurgy: Evidence of a Paradigm Shift?

Practicioners of archaeological and historical metallurgy have begun to identify their discipline by a new term: archaeometallurgy. Tracing the roots of this discipline shows that up to about 1980 the focus of study was on the technical examination of metal objects and determining site plans of metallurgical installations. Essentially it was a study of ancient metals of interest to historians of art or of technology. The focus then shifted to other materials and their archaeological contexts, processing byproducts such as slag, matte, furnace linings and furnace bottoms, crucibles, molds, cupels and tuyeres which are often more abundant on sites than metal. Thus the field of study has been enlarged beyond metallurgy to an interdisciplinary undertaking of materials science, archaeology, and material culture. Simultaneously with this shift in focus came the application of newly-developed instrumentation which supported a parallel shift in methodology from one emphasizing chemical analysis and microstructure to one of materials characterization, emphasising properties and performance.

Metals of music

Abstract Musical instruments, such as brass wind instruments, flutes, organs, and bells, use metals in many forms. Two of these forms—bronze gongs of the Ifugao and iron harpsichord strings of the Baroque period—were studied in the Smithsonians Conservation Analytical Laboratory. The ferrous strings from harpsichords of the 18th Century were drawn from iron that was strengthened with phosphorus, not steel, as had been supposed from their evident strength. The gongs were made from a high tin (ca. 22–23%) bronze alloy by a technique of hot forging and quenching more familiar from the smithing of iron. This alloy and its forming technique were in use for millennia, only recently being superseded in modern metallurgical applications by stainless steel.

High-Tin Bronze Gong Making

Over the last twenty years, there has been a discernable increase in the number of scholars who have focused their research on metal production, working and use in antiquity, a field of study which has come to be known as archaeometallurgy. Materials scientists and conservators have worked primarily in the laboratory while archaeologists have conducted fieldwork geared to the study of metal technology in a cultural context with laboratory analysis as one portion of the interpretive program.

Cyril Stanley Smith’s translations of metallurgical classics

A remarkable contribution of Professor Cyril Stanley Smith was the translation of metallurgical classics into English from several languages -both ancient and modern.

Back to Kitty Hawk: Investigating the first aircraft aluminum

A critical material in aircraft airframe and powerplant construction, aluminum has been employed since the inception of powered flight. Indeed, the Wright bothers’ historic first flight at Kitty Hawk was powered by an engine featuring a crankcase that was cast from aluminum. Long thought to have been destroyed, the original crankcase was recently discovered and analyzed through a combination of historical and scientific research.