Stringent requirements are placed on materials of modern accelerators. Their physical and mechanical properties, machinability, weldability or brazeability are key parameters. Adequate strength, ductility, magnetic properties at room as well as low temperatures are important factors for materials of accelerators working at cryogenic temperatures. In addition, components undergoing baking or activation of Non-Evaporable Getters (NEG) or directly submitted to the impact of the beam impose specific choices of material grades of suitable outgassing and mechanical properties in a large temperature range.
In this first lecture, the metallurgy of stainless steels will be extensively treated. The application of this class of materials, featuring properties unavailable with other alloys, is continuously expanding. These alloys are today prevailing materials for high demanding constructions including vacuum and cryogenic systems, pressure vessels, structural components of accelerator and fusion magnets. Specific metallurgical processes have to be applied in order to obtain adequate purity, inclusion cleanliness and fineness of the microstructure. In many cases these requirements are crucial to guarantee the final leak tightness of vacuum components or adequate properties of structural parts. Steelmaking and processing, thermal treatments and manufacturing aspects allowing such stringent specification requirements to be achieved will be illustrated. A particular attention will be devoted to grades of practical interest for application to particle accelerators, including innovative types, manufacturing and inspection technologies. Magnetic properties and corrosion aspects will also be addressed.
Short bio Stefano Sgobba
Stefano Sgobba graduated in Nuclear Engineering from Politecnico di Milano in 1990 and obtained his PhD in 1994 at the Laboratory of Mechanical Metallurgy of EPFL under the guidance of Prof. Bernhard Ilschner. Immediately after he joined CERN as staff member where he is responsible since 2001 of the materials section, now within the EN-MME group. As from 2009 he is also in charge of the metallurgical and material testing support provided by CERN for the construction of the ITER Magnet System, in the framework of the CERN-ITER Cooperation Agreement. His main research interests are in the field of development and assessment of materials and processes for very low temperature and vacuum applications for high energy physics and fusion technology. He received several prizes, including the "Prix des matériaux" 1994 of a value of 10,000 CHF awarded by Ciba Geigy SA and EPFL for his PhD thesis and the ASM International award for the development of the Powder Metallurgy HIPed End Covers for the LHC Project in 2004. He is author or co-author of more than 120 scientific publications.
Massimo Giovannozzi / 161 participants