报告题目：Complexity in metallic alloys and compounds
主 讲 人：Jean-Marie DUBOIS
Complexity in metallic alloys and compounds
1 Institute Jožef Stefan, Department for Nanostructured Materials, Jamova Cst. 39,
2 Institut Jean Lamour (UMR 7198 CNRS – Université de Lorraine), Parc de Saurupt
CS50840, F-54011 Nancy
3 International Associated Laboratory PACS2 CNRS-UL-JSI
The lecture will focus on A-B-C ternary alloys, in which the elemental constituents A, B and C are chosen in such a way that B-C interactions are repulsive, but A-B and A-C are attractive in the respective binary systems. Such “push-pull alloys” are reminiscent of amplifiers designed to amplify electric signals because they amplify complexity in intermetallics, forming complex compounds with tens to thousands atoms per unit cell. Few of them lead to the ultimate degree of complexity, when quasiperiodic order substitutes for crystal periodicity, thus opening the way to the discovery of unprecedented properties such as heat insulation in Al62Cu25Fe13 (at.%). Many more compounds are known today, which share the same elemental characteristics (the picture may be extended to specific binary alloys by referring to salient features of the electronic density of states). The case of push-pull alloys will be exemplified with data obtained from few in-depth studies of quasicrystal-forming systems such as Al-Cu-Fe or Al-Pd-Mn. Special attention will be placed on the potential usefulness of coatings and composites made thereof. New insight gained on (Gd,Al)-Cu-Fe metallic glasses will also be presented, especially regarding magnetic properties in relation with phase transitions taking place in those glasses upon thermal ageing.