Physics of nanopore healing in condensed matter under the influence of laser radiation and high-temperature plasma

Abstract

The paper theoretically and experimentally investigates the influence of laser radiation and high-temperature plasma on changes in the physical properties of amorphous-nanocrystalline materials with nanopores in a thin surface layer. At present, the possibility of simultaneous increase of hardness and resistance to cracking of the material surface because of selective laser action has been experimentally established. Experimental results can be explained based on the model of selective impact of laser radiation on individual nanopores. The physics of laser selective initiation of healing processes of inhomogeneous/defective areas at the nanoscale has been investigated. Using the proposed physical model, the specificity of selective heating of areas near nanopores, as well as the influence of nanoscale defects in the structure on the specificity of isotherm propagation has also been revealed. The process of healing of nanopores located in the inhomogeneously heated surface layer of the material under the action of shock loading is considered. Theoretical results are compared with experimental data. It is shown that as a result of selective laser treatment it is possible to increase microhardness by three-four times, with simultaneous growth of resistance to cracking under conditions of local loading by the Vickers pyramid. The results obtained can be explained within the framework of ideas about selective laser healing of nano- and micro-sized defects located in the surface layer of the material. Thus, the physical and mechanical properties of the surface of condensed materials in an extreme state caused by strong compression under conditions of simultaneous short-term heating to high temperatures have been studied theoretically and experimentally.