| Abstrakt: |
Scanning electron microscopy and X-ray microspectral analysis are used to study the structure, phase composition, and chemical composition of the heat-resistant alloy formed by high-temperature plasma in nitrogen, with subsequent high-temperature tempering. In the applied alloy, the basic phases are a solid solution of α iron and carbonitrides based on iron, tungsten, chromium, molybdenum, and aluminum (Fe6W6NC and AlN). High-temperature treatment of the applied coating (tempering four times at 580°C, with 1-h holding) increases the lattice constant (from 2.866 to 2.89 Å) and enlarges the coherent scattering regions (from 25 to 100 nm), while the internal elastic stress is decreased (from 1000 to 600 MPa). At the surface of the applied layer, oriented dendritic structure is clearly seen. After subsequent high-temperature tempering, this structure is hardly visible. The microhardness distribution over the depth of the applied layer has a considerable spread, with mean values of 4.412 GPa at the surface (dispersion 1.0956) and 5.153 GPa in the center of the layer (dispersion 1.5697). This spread appears because the multilayer applied material undergoes complex heat treatment over a helical line and the substrate is mixed with the applied coating. High-temperature tempering equalizes the microhardness and increases its mean value to 5.7–6.5 GPa. The hardening of the applied heat-resistant metal mainly appears in high-temperature tempering on account of increase in the quantity of carbide and carbonitride phases and the formation of fine aluminum nitride. [ABSTRACT FROM AUTHOR] |
Full text from SpringerLink