Annual Review of Materials Science 

About: Annual Review of Materials Science is an academic journal. The journal publishes majorly in the area(s): Thin film & Ceramic. It has an ISSN identifier of 0084-6600. Over the lifetime, 487 publications have been published receiving 57542 citations.

Synthesis and Characterization of Monodisperse Nanocrystals and Close-Packed Nanocrystal Assemblies

Abstract: ▪ Abstract Solution phase syntheses and size-selective separation methods to prepare semiconductor and metal nanocrystals, tunable in size from ∼1 to 20 nm and monodisperse to ≤5%, are presented. Preparation of monodisperse samples enables systematic characterization of the structural, electronic, and optical properties of materials as they evolve from molecular to bulk in the nanometer size range. Sample uniformity makes it possible to manipulate nanocrystals into close-packed, glassy, and ordered nanocrystal assemblies (superlattices, colloidal crystals, supercrystals). Rigorous structural characterization is critical to understanding the electronic and optical properties of both nanocrystals and their assemblies. At inter-particle separations 5–100 A, dipole-dipole interactions lead to energy transfer between neighboring nanocrystals, and electronic tunneling between proximal nanocrystals gives rise to dark and photoconductivity. At separations <5 A, exchange interactions cause otherwise insulating ass...

THE MATERIAL BONE: Structure-Mechanical Function Relations

Abstract: ▪ Abstract The term bone refers to a family of materials, all of which are built up of mineralized collagen fibrils. They have highly complex structures, described in terms of up to 7 hierarchical levels of organization. These materials have evolved to fulfill a variety of mechanical functions, for which the structures are presumably fine-tuned. Matching structure to function is a challenge. Here we review the structure-mechanical relations at each of the hierarchical levels of organization, highlighting wherever possible both underlying strategies and gaps in our knowledge. The insights gained from the study of these fascinating materials are not only important biologically, but may well provide novel ideas that can be applied to the design of synthetic materials.

High Rate Thick Film Growth

Abstract: Thick films will be defined here as those sufficiently thick to permit evolutionary selection processes during growth to influence their structures. High rates are defined as those sufficient to deposit thick films in a reasonable time. To avoid superficiality, this review is restricted to evaporation and sputtering, i.e. to physical vapor deposition (PVD). PVD is finding increased use for applications ranging from micro­ electronics to corrosion-barrier and wear-resistant coatings, and to the synthesis of free-standing shapes with unique mechanical properties. The emphasis here is on metallic deposits and on the physics of their growth and structure. Particular attention is given to sputtering, because recent developments ih sputtering tech­ nology make thick film deposition feasible, and because the subject has not been reviewed. Several reviews have concentrated on thick film deposition by evaporation (1, 2). Structure zone models (3-5) [particularly the model proposed by Movchan & Demchishin (3), which predicts three structural forms or zones as a function of T/Tm. where T is the substrate temperature and Tm is the coating-material melting point] have come into increased use in interpreting coating microstructures. There­ fore this review is organized from thc viewpoint of the zone models. After a brief survey of certain pertinent features of evaporation and sputtering, subsequent sections discuss each of the structural zones, metallurgical phase formation, and the mechanical properties of coatings. In this review the structure zones are defined in terms of dominant physical processes rather than structural forms. This generalization permits a broader correlation with experimental observations.

Applications of ultrasound to materials chemistry

Abstract: The chemical effects of ultrasound derive primarily from acoustic cavitation. Bubble collapse in liquids results in an enormous concentration of energy from the conversion of the kinetic energy of the liquid motion into heating of the contents of the bubble. The high local temperatures and pressures, combined with extraordinarily rapid cooling, provide a unique means for driving chemical reactions under extreme conditions. A diverse set of applications of ultrasound to enhance chemical reactivity has been explored with important uses in synthetic materials chemistry. For example, the sonochemical decomposition of volatile organometallic precursors in low-volatility solvents produces nanostructured materials in various forms with high catalytic activities. Nanostructured metals, alloys, oxides, carbides and sulfides, nanometer colloids, and nanostructured supported catalysts can all be prepared by this general route. Another important application of sonochemistry in materials chemistry has been the preparation of biomaterials, most notably protein microspheres. Such microspheres have a wide range of biomedical applications, including their use in echo contrast agents for sonography, magnetic resonance imaging, contrast enhancement, and oxygen or drug delivery. Other applications include the modification of polymers and polymer surfaces.

Shape Memory Alloys

Abstract: In some alloys, a given plastic strain recovers completely when the con­ cerned alloy is heated above a certain temperature. This phenomenon, shape memory effect (SME), was observed in Au-Cd (1) and In-Tl (2) alloys in the first half of 1950s. However, SME was not a focus of research until it was found in a Ti-Ni alloy (3) in 1963, when the phenomenon was first termed the shape memory effect. A similar phenomenon was found in a Cu-AI-Ni alloy as well (3a). At that time, however, SME was considered to be a peculiar phenomenon limited to the specific Ti-Ni alloy. In 1970, Otsuka & Shimizu (4, 4a) unambiguously demonstrated a one­ to-one correspondence between SME and the thermoelastic martensitic transformation in a Cu-AI-Ni alloy. Thus, they concluded that SME is characteristic of alloys exhibiting thermoelastic martensitic trans­ formations. They ascribed the origin to the crystallographic reversibility of the thermoelastic transformation and the presence of a recoverable deformation mode, i.e. twinning, in thermoelastic alloys. Since then, there