Determination of the conditions of nanoporous structures formation in metal materials by pulse-periodic laser treatment

The influence of the laser treatment to create a nanoporous structure in copper-zinc alloy has been searched. Laser treatment of pulse-periodic radiation enables to form a stable stress state on the sample surface at a temperature that does not exceed the melting point. The conditions of nano-pores formation mainly of the channel-type with the depth of the area of nanoporous structure formation not less than 40-45 μm has been ascertained. The re-searches of the surface layer structure of the copper-zinc alloy L62 after laser treatment have shown that in the cross-section the pores are oriented from the surface to the deep of metal and the pores concentration is decreasing with an increase of distance from the surface. The laser treatment creates a nanoporous structure in the surface layer. Temperature and speed modes of treatment which mainly cause the channel-type nanopores formation with a width ~100 nm, which form a nanoporous network, are determined. Likewise the vibration speed measurements of the samples were carried out. Regardless of the external laser exposure frequency the maximum values of the vibration speed occur at almost the same frequencies corresponding to the natural oscillation frequencies, under such conditions the nanoporous structures are formed. Damping device application significantly reduces the vibration speed values. In this case, the formation of the nanopores in the metal material does not occur.