JOM
The record-high thermal conductivity of high-quality diamond makes it a natural choice for many applications in thermal management. The columnar microstructure of chemical-vapor-deposited diamond thick films, however, causes anisotropy and a strong gradient in the conductivity, both of which can be understood in terms of phonon-scattering defects that aggregate near grain boundaries. Techniques to...
Recent research and development on high-strain-rate superplasticity has led to the concept of an accommodation helper mechanism and a new opportunity for superplastic forging. In this article, works about processing for ultrafine-grained materials and deformation mechanisms and high-strain-rate superplasticity applications are reviewed.
Alloys that combine the high electrical and thermal conductivity of copper with the low thermal expansivity and higher strength of Invar (Fe-36Ni), are of interest for a range of applications. In suitable Cu-Fe-Ni alloys, nearly pure copper equilibriates with an Invar-rich solid solution; casting such alloys invariably produces Invar-rich dendrites in a copper-rich solid solution. Two-phase alloys...
The U.S. Department of Energy’s Office of Basic Energy Sciences recently established the Center for Excellence in the Synthesis and Processing of Advanced Materials. Projects at the center typically include several national laboratories, industrial partners, and universities; metal forming is one of eight projects within the center. This article describes the center’s metal forming project, which...
Thermal management is an important issue in electronic packaging due to the increasing complexity, miniaturization, and high density of components in modern devices. In high-power-dissipation packages, heat sinks are essential for preventing thermal damage to heat-sensitive components on the silicon chip. However, commonly used heat-sink materials (e.g., copper and aluminum alloys) have a much higher...
Thomas R. Bieler is the advisor to JOM from the Shaping and Forming Committee of the TMS Materials Processing & Manufacturing Division. Lawrence A. Lalli is with Alcoa Technical Center, and Stuart R. MacEwen is with Alcan International.
This article provides an overview of some of the critical materials issues involved in the utilization and commercialization of aluminum-nitride ceramics in electronic applications. Critical material defects and microstructural issues that control thermal, electrical, and mechanical properties and the status of metallization technology are reviewed. Finally, a discussion of current and future potential...
He is the advisor to JOM from the TMS Electronic Packaging and Interconnection Materials Committee of the Electronic, Magnetic, & Photonic Materials Division.
Transition metal carbides, nitrides, and borides can be called metallic ceramics because they are electronically conductive and extremely hard. Their various applications include cutting and grinding tools, thermal-barrier coatings, diffusion-resistant thin films, interconnects, and superconductivity devices. In each case, the ability of the material to resist or permit heat flow is important. Because...
Arnold B. Silverman is chair of the Intellectual Property Department and a member of Eckert, Seamans Cherin & Mellott, LLC in Pittsburgh, Pennsylvania.
The industrial rolling of aluminum alloys is generally conducted in multistage schedules of 10–15 passes partly on reversing mills and partly on continuous mills with temperature declining from 500°C to between 300°C and 250°C. Static recrystallization may take place in long intervals after passes with higher temperature and strain. During lower temperature intervals, only static recovery takes place...
The recrystallization textures of aluminum alloys can be explained by a growth selection of grains with an approximate 40° 〈111〉 orientation relationship out of a limited spectrum of preferentially formed nucleus orientations. Accordingly, recrystallization textures can be modeled by the multiplication of a function f(g)nucl describing the probability of nucleation of the various orientations with...
He is also the advisor to JOM from the TMS Alloy Phases Committee of the Structural Materials and the Electronic, Magnetic & Photonic Materials Divisions.
Previously, deformation-processed alloys have been prepared by expensive techniques such as vacuum induction melting. An air melting technique has been developed to prepare Cu-7Cr (vol.%) alloys using a modified standard tilt pour induction melting furnace. The technique avoids oxidation of the chromium by the use of a blanket of argon gas and forced submersion of the chromium in the copper melt....
Conclusions Although the findings are from disparate contexts, they demonstrate a long familiarity of Indian metal workers with the use of tin and with manipulating bronze alloys to exploit the functional properties of phases and intermetallic compounds. Thus, the copper-bronze tradition in southern Indian antiquity and in the Indian subcontinent has more depth than suspected, with some evidence for...