Material Science Aspects of Alloy Modification by Nanocompositions of Plasma-Chemical Synthesis

Abstract

Crystallographic characteristics of nanodispersed materials obtained by plasma-chemical synthesis were studied. Using industrial equipment for plasma-chemical synthesis the nanodispersed powders of high-melting carbide, nitride, carbonitride and silicide class compounds based on titanium, magnesium, aluminium, silicon were obtained. Technology for synthesis of powder fraction less than 100 nm was developed. The efficiency of nanodisperce compositions use in smelting of structural steels was determined. In the result of 10Г2С steel modification with Ti (CN) nanopowder strength, plastic properties and impact toughness were improved. Elemental composition of nanodispersed composition was determined: SiC, TiC, TiN, Ti (CN), AlN, Mg2Si, Mg3N2. The elemental composition of synthesized compounds corresponded to stoichiometric composition. Microdiffractional patterns of the particles were analysed, it was shown that nanopowders belong to the solid crystalline bodies with metallic bond. It has been found, that titanium carbonitride Ti (CN) particles have face-centered and silicon carbide (SiC) particles have hexagonal crystal lattice. Experiments for steel 10Г2 and 10Г2С modifying with nanopowder compositions on base of Ti (CN) and SiC were carried out. The efficiency of nanodisperce compositions use in smelting of structural steels was determined. In the result of 10Г2С steel modification with Ti (CN) nanopowder strength, plastic properties and impact toughness were improved. The choice of nanodisperce titanium carbonitride Ti (CN) powders with 100 nm fraction for light alloy steels modifying was justified. The required criteria for choice of nanopowder modifiers were obtained: insolubility in smelt, correspondence of crystal lattice to steel matrix, commensurability with austenite germ critical radius in crystallizing.