Christian Paglia

University of Applied Sciences of Southern Switzerland, Switzerland

Title: Mechanical properties and environmental degradation in high strength aluminum alloys

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Biography

Christian Paglia completed his Ph. D in Material Science at the Swiss Federal Institute of Technology, in collaboration with Sika AG in Zurich. Post-doctoral Researcher at the Fontana Corrosion Center in the Corrosion of Aerospace Aluminum Alloys Friction Stir Welds at the Material Science Department, Ohio State University, Columbus, USA, in collaboration with the Wright Patterson Air Force Research Laboratories. He is responsible of a branch office of the Helbling Consulting Engineering Group, Zurich. He is the Director of the Institute of Materials and Constructions at the University of Applied Sciences of Southern Switzerland. He had several publications on concrete, metals and other materials. He is an Editorial board member of materials and corrosion scientific journals. Member of the SIA commission 215 on mineral binders. He is also a Member of the commission for the evaluation of the impartiality of the Swiss certification body for construction products S-CERT AG (CH) / S-CERT FL GmbH (FL).

Abstract

High strength aluminum alloy are used in the aircraft industry. The metal alloys are exposed to severe condition, alternatively varying in temperature and exposition to aggressive environment. The 7075-T651 and 7050-T7451 aluminum alloy represent some of the alloys used. Therefore, their mechanical properties and environmental degradation must be clearly investigated. This was carried out in this work by testing the alloys in the different tempers and by alternatively exposing them to a variation in temperature and in the aggressive environment, such as 20^oC and 65% relative humidity, to a 3.5 weight % NaCl solution and by refrigeration at -20^oC. The aluminum alloy in the annealed condition exhibits higher elongation as compared to the T-651 and T-7451 temper. The mechanical properties reach 500 Mpa. The T-651 temper exhibits a significant reduction in strain. Similar deformation but lower strength for the T-7451 temper as for the T-651 is observed. The environmental susceptibility of the 7075-T651 and 7050-T7451 at 20 ^oC is generally high with the alternate exposure to NaCl solutions and dry atmosphere (ductility ratio 0.5 to 0.7) respectively, while is generally reduced by the alternate exposition at low temperature because of the reduction of localized corrosion and initiation failure sites.