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The present paper focuses on the technological approach to manufacturing composite in the form of Inconel 625 reinforced with tungsten carbide particles. Twenty-four samples with reinforcement amounts ranging from 30 to 90% (wt.%) and different numbers of deposited layers were manufactured with the use of Laser Engineered Net Shaping (LENS). The metallurgical quality, microstructure, chemical and phase composition as well as hardness of the produced composites were determined. Digital microscopy, X-ray powder diffraction and SEM-EDS were employed for this purpose. Despite numerous cracks, the fabricated samples exhibited a greater hardness than single-layer coatings of analogous composition also produced by additive techniques. This phenomenon is likely a result of repeated crystallization of the composites in remelted areas. A dual mechanism of material strengthening is observed in the additively manufactured composites, both by the presence of reinforcing particles and precipitates of secondary phases. [ABSTRACT FROM AUTHOR]

Samples of 316L SS were manufactured by Laser Engineered Net Shaping (LENS ® ) using different technological parameters. The deposited samples were investigated in terms of microstructure, mechanical properties, phase content and corrosion resistance (salt chamber and electrochemical corrosion). Parameters were chosen to obtain a proper sample built for layer thicknesses of 0.2, 0.4 and 0.7 mm by changing the laser feed rate while keeping the powder feed rate constant. After a comprehensive analysis of the results, it was found that the manufacturing parameters slightly affected the resulting microstructure and also had a minor impact (almost undetectable considering the uncertainty of the measurement) on the mechanical properties of samples. Decreases in resistance to electrochemical pitting corrosion and environmental corrosion with an increased feed rate and a decrease in layer thickness and grain size were observed; however, all additively manufactured samples were found to be less prone to corrosion than the reference material. In the investigated processing window, no influence of deposition parameters on the phase content of the final product was found-all the samples were found to possess austenitic microstructure with almost no detectable ferrite.

The laser engineered net shaping (LENS®) process is shown here as an alternative to melting, casting, and powder metallurgy for manufacturingiron aluminides. This technique was found to allow for the production ofFeAl and Fe 3 Al phases from mixtures of elemental iron and aluminum powders. Theinsitusynthesis reduces the manufacturing cost and enhances the manufacturing efficiency due to the control of the chemical and phase composition of the deposited layers. The research was carried out on samples with different chemical compositionsthat were deposited on the intermetallic substrates that were produced by powder metallurgy. The obtained samples withthe desired phase composition illustrated that LENS® technology can be successfully applied to alloys synthesis.