In an attempt to meet the demand for new ultra-high strength materials, the processing of novel material configurations with unique microstructure is being explored in systems which are further and further from equilibrium. One such class of emerging materials is the so-called nanophased or nanostructured materials. This class of materials includes metals and alloys, ceramics, and polymers characterized by controlled ultra-fine microstructural features in the form oflayered, fibrous, or phase and grain distribution. While it is clear that these materials are in an early stage of development, there is now a sufficient body of literature to fuel discussion of how the mechanical properties and deformation behavior can be controlled through control of the microstructure. This NATO-Advanced Study Institute was convened in order to assess our current state of knowledge in the field of mechanical properties and deformation behavior in materials with ultra fine microstructure, to identify opportunities and needs for further research, and to identify the potential for technological applications. The Institute was the first international scientific meeting devoted to a discussion on the mechanical properties and deformation behavior of materials having grain sizes down to a few nanometers. Included in these discussions were the topics of superplasticity, tribology, and the supermodulus effect. Lectures were also presented which covered a variety of other themes including synthesis, characterization, thermodynamic stability, and general physical properties.

The mechanical properties of materials strongly depend on their microstructure. Therefore, engineering the material's microstructure can lead to improving its mechanical properties. One method for enhancing the strength of metallic materials consists of refining the grain size down to the nanometer scale. Such nanostructured materials possess remarkable strength without using conventional metallurgical strengthening methods. However, this strength often comes at the expense of workhardening capacity, thus favoring flow localization and loss of ductility and toughness. The deformation behavior of nanostructured metallic materials has been extensively studied in the literature. However, little is known of their fracture behavior. In this study, the mechanical behavior of a nanostructured, nearly pure material is investigated in order to link processing conditions, microstructure, and fracture locus in stress space. With focus laid on BCC materials which can undergo a ductile-to-brittle transition, Interstitial- Free (IF) steel is chosen. The microstructure is refined using Severe Plastic Deformation (SPD) to achieve ultra-fine grain (UFG) materials with grain sizes in the range 100nm- 1 mu m. Equal Channel Angular Extrusion (ECAE) is used to obtain three types of UFG-IF steel microstructures by varying the extrusion rate and processing temperature. The deformation behavior is investigated for the three UFG materials using round smooth bars and is compared with the behavior of the as-received material. The damage behavior and the fracture mechanisms are studied using tensile round notched bars with varying notch radii. The findings indicate a remarkable combination of strength and notch ductility at room temperature, including for the material with the finest microstructure. They also point to the need for careful characterization of temperature effects before such materials can be considered in structural applications.

Synthesis and Properties of Advanced Materials provides an overview of some of the most exciting developments in advanced materials. The book contains review papers based on tutorial lectures given at The First Pan American Advanced Study Institute held in Merida, Mexico, 1995. Each paper serves as a comprehensive introduction and review to the topic covered. Topics included: diamond and related materials, nanocrystalline metals and ceramics, Co-based alloys for biomedical applications, high-temperature superconductivity materials, composite materials, cement-based materials, ion-implanted ceramics and structural ceramics. Each chapter emphasizes the relationships among processing parameters, micro-structure and properties. Synthesis and Properties of Advanced Materials provides an excellent review of the state of the art in advanced materials for the working engineer or researcher. Students will also find this text an accessible introduction to the field.

Special topic volume with invited peer reviewed papers only

Nanocrystalline (NC) and Ultrafine-grained (UFG) metal films exhibit a wide range of enhanced mechanical properties compared to their coarse-grained counterparts. These properties, such as very high strength, primarily arise from the change in the underlying deformation mechanisms. Experimental and simulation studies have shown that because of the small grain size, conventional dislocation plasticity is curtailed in these materials and grain boundary mediated mechanisms become more important. Although the deformation behavior and the underlying mechanisms in these materials have been investigated in depth, relatively little attention has been focused on the inhomogeneous nature of their microstructure (particularly originating from the texture of the film) and its influence on their macroscopic response. Furthermore, the rate dependency of mechanical response in NC/UFG metal films with different textures has not been systematically investigated. The objectives of this dissertation are two-fold. The first objective is to carry out a systematic investigation of the mechanical behavior of NC/UFG thin films with different textures under different loading rates. This includes a novel approach to study the effect of texture-induced plastic anisotropy on mechanical behavior of the films. Efforts are made to correlate the behavior of UFG metal films and the underlying deformation mechanisms. The second objective is to understand the deformation mechanisms of UFG aluminum films using in-situ transmission electron microscopy (TEM) experiments with Automated Crystal Orientation Mapping. This technique enables us to investigate grain rotations in UFG Al films and to monitor the microstructural changes in these films during deformation, thereby revealing detailed information about the deformation mechanisms prevalent in UFG metal films.

This book delivers practical insight into a broad range of fields related to hard coatings, from their deposition and characterization up to the hardening and deformation mechanisms allowing the interpretation of results. The text examines relationships between structure/microstructure and mechanical properties from fundamental concepts, through types of coatings, to characterization techniques. The authors explore the search for coatings that can satisfy the criteria for successful implementation in real mechanical applications.

This second edition of Handbook of Micro/Nanotribology addresses the rapid evolution within this field, serving as a reference for the novice and the expert alike. Two parts divide this handbook: Part I covers basic studies, and Part II addresses design, construction, and applications to magnetic storage devices and MEMS. Discussions include: surface physics and methods for physically and chemically characterizing solid surfaces roughness characterization and static contact models using fractal analysis sliding at the interface and friction on an atomic scale scratching and wear as a result of sliding nanofabrication/nanomachining as well as nano/picoindentation lubricants for minimizing friction and wear surface forces and microrheology of thin liquid films measurement of nanomechanical properties of surfaces and thin films atomic-scale simulations of interfacial phenomena micro/nanotribology and micro/nanomechanics of magnetic storage devices This comprehensive book contains 16 chapters contributed by more than 20 international researchers. In each chapter, the presentation starts with macroconcepts and then lead to microconcepts. With more than 500 illustrations and 50 tables, Handbook of Micro/Nanotribology covers the range of relevant topics, including characterization of solid surfaces, measurement techniques and applications, and theoretical modeling of interfaces. What's New in the Second Edition? New chapters on: AFM instrumentation Surface forces and adhesion Design and construction of magnetic storage devices Microdynamical devices and systems Mechanical properties of materials in microstructure Micro/nanotribology and micro/nanomechanics of MEMS devices