D. Kotoban

Comparison of Additive Technologies for Gradient Aerospace Part Fabrication from Nickel-Based Superalloys

In our papers, the laser beam-aided control of the self-propagating high-temperature synthesis in Ni–Al systems for the layerwise manufacture of three-dimensional (3D) parts was offered and experimentally realized. As for the laser in situ synthesis of NiAl and Ni3Al intermetallides and their layerwise laser cladding without any visible cracks and pores, it was successfully performed later on. The present chapter is dedicated to the comparison of optimal conditions for the selective laser melting and laser direct metal deposition processes of the nickel-based powders and fabrication of a full-density, functionally graded, and crack-free structures on the maximum deposition rate for technological applications. The effects of laser parameters on the phase composition and microstructure of the resulting intermetallic samples will be discussed. The possibility of controlling to change the hardness of the gradient structures from layer to layer by changing of the powder composition and by using the reinforced intermetallic inclusions into superalloy matrix widens the range of possible applica‐ tions of 3D parts in aerospace and nuclear industries. Comparing different methods of additive manufacturing reveals their advantages and disadvantages for making large samples, scalability, and customizability, finding ways to control the distribu‐

New Approach of True Temperature Restoration in Optical Diagnostics Using IR-Camera

The laser treatment processes are specified due to the laser-matter interaction instabilities. Modern additive manufacturing technologies such as selective laser melting provide layer-by-layer part growth with continuous operation for hours and days but without adequate controlling systems at present. In this paper, a method for determining a temperature in the laser action zone during the process based on a study of microscopic structure, phase and element analyses of the processed material is proposed. A fixed point corresponding to melting temperature was acquired, and the corresponding emissivity coefficient was calculated with the assumption of its wavelength and temperature independence. The experimental data were corroborated with good agreement with mathematical calculations. The obtained results reveal an impact of scanning speed and of laser emission power on temperature in molten zone, which presents interest for optimization of laser-processing technologies and more specifically selective laser melting process parameters.

Comparative Study of Selective Laser Melting and Direct Laser Metal Deposition of Ni3Al Intermetallic Alloy

The Ni3Al intermetallics involve more attention because of inherent material properties especially interesting in high temperature application. In this study the Selective laser melting (SLM) and Direct laser metal deposition (DLMD) are used to manufacture the single-tracks and layers. For the comparison of the methods, the optical microscopy, SEM, XRD and EDX microelement analysis were involved. The materials show no significant differences but each SLM and DLMD have the target application.

Experimental study of conditions for the 3D laser cladding of nickel aluminide

The layerwise laser cladding of powdered alloy based on intermetallic gamma Ni3Al phase is studied. The effect deposition parameters have on the geometry of the deposited beads is shown. Microstructures are investigated and the cracking susceptibility of the deposited material is analyzed. The effective deposition parameters are determined within a range of specific laser energy inputs of (2–8) × 106 J kg−1 at beam scanning rates of (1.67–10) × 10−3 m/s and a powder feed of 6.3 × 10−5 kg/s−1.