Research Advancements In The Field Of Materials Science

This book has a straightforward format and is written in a specific style for an easy read, making it accessible to a broad audience of students and academics. The research projects covered in this book are related to non-crystalline solids and various crystal functional materials, including single-crystal silicon film on glass, CaF2 laser components, AlxGa1- xAs laser diode, synthetic diamonds, hard TiN/AlN superlattices, YBCO superconductors, etc. The emphasis is on discovering the relationship between the property of materials and their internal structures and using this information to improve the materials' performance. In materials science, the particular problem concerning the nature of glass state and glass transition has challenged researchers for many decades. It was selected by the journal Science in 2005 as one of 125 key, unanswered scientific questions. This book attempts to provide an answer by proposing a new medium-range structural model for silica and silicate glasses. The model correlates glass structures with and explains many of glass physical properties, such as viscosity behavior in a wide temperature range, endothermic effects, strength and brittleness, indentation cracking behavior, etc. When applied to the structural evolution in the glass formation cooling process, the model suggests that the glass transitions exhibit characteristics of a second-order phase transition. These new results may be interesting to the broad scientific community. The application of various TEM characterization techniques are also covered in this book. Traditional diffraction contrast images was used to study twin interface structure and dislocation defects inside the crystals; the Fresnel contrast technique was used to study the nanophase separation of borosilicate and soda lime silicate glasses; HRTEM was used to study the roughness of interface and crystal defects; ELNES was used to examine the valance state, and the coordination of elements; Kramers-Kronig analysis of EELS data was used to study the band gap energy and transmission properties of optical components; and ALCHEMI technique was used to determine element site occupancy in perovskite crystals structure. Researchers in materials science and engineering can apply these characterization techniques to many other projects. This book provides a new glass structure model and many examples of using proper analytical tools to solve practical problems related to materials. This is a unique book in terms of the depth and complexity with which the subject is discussed. Tables, equations, and approximately one hundred illustrations are used to illustrate the data.