A method is proposed for creating principally new functionally graded heterogeneous materials on the basis of B4C ceramic powders with different mass fractions in the original mixture and plastic meta

The quality of cutting of low-carbon and stainless steel by beams of fiber and CO lasers with oxygen or nitrogen being used as a process gas is compared. The cut surface roughness for sheets from 3 to 10 mm thick is determined. Domains of optimal (in terms of the minimum roughness criterion) application of lasers of various types in the space of dimensionless parameters (Peclet number and dimensionless power) are found. It is demonstrated that the CO laser is more effective for laser-oxygen cutting, while the fiber laser is more beneficial for cutting with the use of a neutral gas.

The fiber and CO2 laser were compared from the viewpoint of two laser-cutting methods: the oxygen-assisted cutting of low-carbon steel and fusion cutting of stainless steel with a neutral assistant gas. The absorbed laser energy was measured in respect to the unit of the removed material volume at the cutting parameters correlating to the minimal roughness of the cut surface. This value equals to 11..13J/mm3 both for the fiber and CO2 lasers. During the fiber-laser cutting, the minimal roughness is reached at the Peclet number 0.35..0.4, at the CO2-laser cutting – at 0.45..0.55. At the fusion cutting of stainless steel, the minimal roughness is reached at the maximal cutting speed. The maximal cutting speed has the higher value in the fiber-laser case at the same laser power. The paper discusses the potentiality of the method of absorbed laser energy measurement by the value difference at the cut channel inlet and outlet

The paper presents the results of an experimental study of the microstructure and microhardness of a functionally gradient material fabricated from 316L stainless steel and tungsten carbide (WC) ceramic particles by the selective laser melting method. High-quality defect-free cermet coatings with different ceramic contents were obtained. Optical and scanning electron microscopy and energy dispersive analysis show that laser processing leads to dissolution of WC ceramic particles. The produced coating has a dendritic structure and contains iron- and chromium-based carbides. The coating microhardness is in the range HV_0.3 = 280 – 430.

The influence of the laser beam parameters (power, motion velocity, and focus position) on the characteristics of the track being formed (size, elemental composition, and microhardness) is studied....