Aerospace Alloys

The aerospace field is traditionally strategic for the development of novel materials needed for the specific requirements of aircraft structures and propulsion systems. A large number of advanced materials and relevant processing routes have been implemented first for aerospace needs. On many occasions, aerospace materials and technologies have subsequently been transferred successfully to a wider range of applications, like chemical industry, energy production, nuclear plants, terrestrial and marine transportation, and many more. The aim of this book is to present an overview of the main classes of metallic materials, like light alloys (Al-, Mg-, and Ti-based, including Ti-aluminides), steels, superalloys, refractory alloys, oxide dispersion strengthened alloys, ordered inter- metallics, shape memory alloys, and related systems, e.g., laminate composites and coatings. The basic concepts concerning the structure of aircrafts and the working princi- ples of gas turbine engines are recalled to provide the reader with indications on the specific needs and possible issues in this field, so that the adoption of given materials systems and relevant processing routes are better understood. The content of the book is organized according to the main classes of materials that are of actual and potential interest for aerospace applications. In each chapter, materials properties and relevant technological aspects, particularly as concerns processing, are presented. The motivations that have guided the research efforts for the development of new materials systems have changed over the comparatively short life of aeronautics. Nowadays, energy-saving and environmental issues are paramount: these stand points and their role in materials development are also highlighted. A deliberate attempt, pursued in writing Aerospace Alloys, has been to include an updated bibliography and indication of further readings, both important in a contin- uously evolving field. A list of general references concerning materials science and engineering and physical metallurgy is included among the “Further Readings” lists at the end of each chapter. In this way, the fundamental aspects of these disciplines, vii viii Preface which may contribute to a better understanding of the book content, can easily be recovered. We believe the book can be used in advanced undergraduate courses in materials and mechanical engineering, considering that the starting point for writing this book has been a collection of lecture notes of courses that SG ran over several years at the University of Trento and the University of Florence in Italy. However, we would expect that the subject and relevant materials information may also be of interest to researchers working in R&D industrial laboratories, considering that in this perspec- tive, we have included compositional tables, some in the appendices, so that the textbook turns out be reasonably self-consistent. We believe that the mixed aca- demic (SG’s) and industrial (AM’s) background may provide original and comple- mentary stand points on the different subjects, attracting the interest of researchers and professionals working in the different but still strongly interacting development laboratories in the academia and industry. We conclude this preface with the acknowledgments. In the first place, we wish to thank all the students (AM has been one of them at some stage!), who during the lecture classes placed questions and contributed to a stimulating discussion, pro- moting in this way the improvement and correction of the lecture notes. We also thank our colleagues for stimulating discussions and suggestions on several subject dealt in the book.