Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Concentrated energy beams in advanced materials development

Surface processing is investigated systematically by means of concentrated energy beams, laser, electron beam, plasma and concentrated solar energy. These techniques are unique for tailoring surface properties such as extended solid solutions, metastable crystalline phases, and metallic glasses. The project develops the required scientific background of the advanced technology, based on concentrated energy beams (CEB) action, for the production of protective coatings and surface layers based on innovative materials fabrication. The following CEB were used: laser, combined laser/laser action, electron beam, concentrated solar energy and combined solar energy/plasma action.

Investigation of the near surface laser plasma and its influence on alloying process by high speed photorecording of erosion plume dynamics and melt ejection has allowed optimization of the laser alloying process. Rather uniform tin and lead high concentration profiles have been produced in the subsurface regions. Based on the experimental investigation of the main heat transfer and mass transfer regularities, the model describing heat transfer and mass transfer was proposed and checked for actual treatment parameters. This study can be considered as a new stage in further development of an aluminum matrix with a better lubrication capability than conventional aluminium alloys by laser surface alloying (LSA) for use in particular tribological structures. The development can result from the presence of a fine dispersion of lead or tin spherical inclusions in a local alloyed near-surface region. Encouraging results were obtained in both the cases of LSA of pure aluminum with lead or tin from predeposited multilayer coatings. In different metallic solid solutions a new nonequilibrium structural state arises accompanied by the significant or even anomalously large change of the alloy properties. Thus, the new structural states are the dissipative structures which can be described in terms of nonlinear nonequilibrium thermodynamics.

Reported by

Centre National de la Recherche Scientifique
Avenue Prof. Trombe
66125 Odeillo - Font-Romeu
France
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