TOPOGRAPHY OF GRAIN BOUNDARIES VARIED BY SHORT PULSE LASER IRRADIATION FOR CONTROLLING MICROSTRUCTURES OF METALS

摘要

A visualization method of metal grain boundariesrnwith a short pulse laser has been developed. Thisrnvisualization method was required for selecting grain inrnlocal heating system with a CW (continuous wave)rnfiber laser for controlling grain structures. Two kinds ofrnshort pulse lasers, nanosecond and femtosecond lasers,rnwere used in the experiments for promoting thernvisualization. The sample metal was a pure aluminumrn(99.59%) plate. The topography of the grain boundaryrnregions was changed by the nanosecond laserrnirradiation. This topography change enabled thernvisualization of the grain boundaries.