**Preface to "Characterization of Welded Joints"**

The Characterization of Welded Joints book follows the intense research that continues to be carried out around a manufacturing process which is as important in the context of metalworking as it is in welding. Although welding brings together a set of processes that are quite old, significant developments have emerged in new processes and variants to existing processes, as a result of the continuous research that a wide range of researchers around the world continue to develop. In addition, the development of new materials, both in the field of metallic alloys and polymeric materials, induces the need to develop new investigations for the optimization of parameters and the weldability of these new materials, leading to numerous investigations in the area of the characterization of welded joint. This book brings together an interesting set of contributions that make it possible to understand, in a clear way, some phenomena directly related to certain welding processes, focusing on the processes and their parameters, their surroundings, such as heat treatments, and materials. About a third of the book is dedicated to developments around friction stir welding, probably one of the most investigated processes today, and still with a large potential to be investigated. Since welding is a process capable of generating numerous defects, some of which may constitute serious threats to the integrity of the welded assembly, the in-depth study of process/material binomials is extremely useful. Being a book created based on chapters developed by different groups of authors, the knowledge brought becomes even more effective, due to the fact that these contributions are brought by true specialists in each area, and the work has been reviewed by experts in the same area. Thus, the necessary conditions were created so that this book could bring high added value in terms of knowledge to the entire scientific community, with special attention to PhD students in this area and to professors who regularly teach these themes and seek a continuous update of their knowledge in this area. The authors hope that their contribution can be a real asset in increasing the knowledge of those who study and research in this field.

> **Francisco J. G. Silva** *Editor*
