Search Results for angular distribution

This article presents a general description of pulsed-laser deposition. It describes the components of pulsed-laser deposition equipment. The article also discusses the effects of angular distribution of materials. Finally, the article reviews the characteristics of high-temperature superconductors and ferroelectric materials.

The principal objective of quantitative fractography is to express the characteristics of features in the fracture surface in quantitative terms, such as the true area, length, size, spacing, orientation, and location. This article provides a detailed account of the development of more quantitative geometrical methods for characterizing nonplanar fracture surfaces. Prominent techniques for studying fracture surfaces are based on the projected images, stereoscopic viewing, and sectioning. The article provides information on various roughness and materials-related parameters for profiles and surfaces. The applications of quantitative fractography for striation spacings, precision matching, and crack path tortuosity are also discussed.

This article provides a detailed account of the basic concepts of Rutherford backscattering spectrometry (RBS). It begins with a description of the principles of RBS, as well as the effect of channeling in conjunction with backscattering measurements and the effect of energy loss under this condition. This is followed by a section on equipment used in RBS analysis. Channel-energy conversion, energy-depth conversion, and separation of the dechanneling background are then discussed as the main steps of RBS data analysis. The article also discusses the applications of RBS—including composition of bulk samples, thin-film composition and layer thickness, impurity profiles, damage depth profile, and surface peak—as well as the various codes developed to simulate it.

The quantitative characterization of fracture surface geometry, that is, quantitative fractography, can provide useful information regarding the microstructural features and failure mechanisms that govern material fracture. This article is devoted to the fractographic techniques that are based on fracture profilometry. This is followed by a section describing the methods based on scanning electron microscope fractography. The article also addresses procedures for three-dimensional fracture surface reconstruction. In each case, sufficient methodological details, governing equations, and practical examples are provided.

The Mossbauer effect (ME) is a spectroscopic method for observing nuclear gamma-ray fluorescence based on recoil-free transitions in a nucleus embedded in a solid lattice. This article provides an overview of the fundamental principles of ME and related concepts such as recoil-free fraction, absorption cross section, gamma-ray polarization, isomer shift, and quadrupole and magnetic interactions. It illustrates the experimental arrangement for obtaining ME spectra and presents several application examples.

The Mossbauer effect (ME) is a spectroscopic method for observing nuclear gamma-ray fluorescence using the recoil-free transitions of a nucleus embedded in a solid lattice. This article provides an overview of the fundamental principles of ME, covering recoil-free fraction, absorption, selection rules, gamma-ray polarization, isomer shift, quadrupole interaction, and magnetic interaction. Experimental arrangement for obtaining ME spectra is described and several examples of the applications of ME are presented. The article contains tables listing some properties of Mossbauer transitions and principal methods used for producing ME sources.

This article describes the formation of residual stresses and distortion, providing information on the techniques for measuring residual stresses. It presents a detailed discussion on the magnitude and distribution analysis of the residual stresses and distortion in weldments. The article briefly explains the effects of residual stresses and distortion on the brittle fracture and fatigue fracture of welded structures. It also provides information on the thermal treatments of weldments.

This article discusses the fractal characteristics of fracture surfaces as a means for describing and quantifying irregular, complex curves and surfaces of fractured materials. It describes the important relationship between the profile and surface roughness parameters that yield the surface area of irregular fracture surfaces. The article reviews the experimental procedures required to obtain profiles and measurements that are made. In addition, fractal equations that linearize all the experimental data and provide constant fractal dimensions are presented in the article. Modified fractal dimensions that result from these analyses appear to possess some generality for natural irregular nonplanar surfaces and their profiles.

This article describes the formation of residual stresses and distortion and the techniques for measuring residual stresses. It provides a discussion on the magnitude and distribution analysis of residual stresses and distortion in weldments. The article considers the effects of residual stresses and distortion on the brittle fracture and fatigue fracture of welded structures. The thermal treatments of weldments are also discussed.

Rutherford backscattering spectrometry (RBS) is a major materials characterization technique that can provide information in a short analysis time. It is used for quantitative compositional analysis of thin films, layered structures, or bulk materials and to measure surface impurities of heavy elements on substrates of lighter elements. This article focuses on RBS and its principles, such as collision kinematics, scattering cross section, and energy loss. It describes the channeling effect and the operation of the RBS equipment. The article also provides information on the applications of RBS.

Fusion welding induces residual stresses and distortion, which may result in loss of dimensional control, costly rework, and production delays. In thermal analysis, conductive heat transfer is considered through the use of thermal transport, heat-input, and material models that provide values for the applied welding heat input. This article describes how the solid-phase transformations that occur during the thermal cycle produced by welding lead to irreversible plastic deformation known as transformation plasticity. Residual stress and welding distortion are also discussed.

The objective of quantitative metallography/stereology is to describe the geometric characteristics of the features. This article discusses the geometric attributes of microstructural features that can be divided into: the numerical extents and the number density of microstructural features; derived microstructural properties; feature specific size, shape, and orientation distributions; and descriptors of microstructural spatial clustering and correlations. It emphasizes on the practical aspects of the measurement techniques and applications. The article also provides information on the quantitative metallographic methods for estimation of volume fraction, total surface area per unit volume, and total length of per unit volume.