Two seminars by Prof. Kaveh EDALATI, Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395, Japan


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Date | Time
09/03/2016 | 2 h 00 min - 6 h 00 min

Location
Salle Klepaczko

Categories


14h: A historical review on high-pressure torsion from 1935 to 1988

High-pressure torsion (HPT) is currently on of the most popular severe plastic deformation techniques to create ultrafine-grained materials with novel structural and functional properties. The method is receiving significant attention mainly because of the reports of Prof. Ruslan Z. Valiev and his co-workers in 1988 on the efficiency of the method in creating nanostructured metals. The HPT method was first introduced in 1935 by Prof. Percy W. Bridgman at Harvard University. Bridgman pioneered application of high torsional shearing stress combined with high hydrostatic pressure to many different kinds of metallic materials, minerals, glasses, polymers, lubricants and many other kinds of organic and inorganic compounds. This talk reviews the main findings of Bridgman and his successors (1935-1988) and explains their historical importance in advancement of materials and methods.

14h45 : Significance of severe plastic deformation on hydrogen storage performance

This talk reviews some major findings on the significance of severe plastic deformation on the hydrogen storage properties of metal hydrides, achieved at Kyushu University. The method of high-pressure torsion (HPT) is employed to introduce severe plastic deformation in different kinds of Mg-based and Ti-based hydrogen storage materials. Our main targets are reducing the thermal stability of Mg-based hydrides and easy activation of Ti-based hydrides. Several interesting results are found: increasing the hydrogenation kinetics; easy activation for hydrogen storage; improvement of the air resistance (difficult deactivation); and synthesis new nanostructured materials for hydrogen storage at room temperature. These unique properties are due to the formation of different kinds of lattice defects (dislocations, grain boundaries, stacking faults and fine cracks) and/or formation of new phases.