The paper is devoted to the direct energy deposition (DED) of functionally graded materials (FGMs) created from stainless steel and aluminum bronze with 10% content of Al and 1% of Fe. The results of the microstructure analysis using scanning electronic microscopy (SEM) demonstrate the existence of a dendritic structure in the specimens. The crystallization rate of the gradient binary Cu-Fe system structures was investigated and calculated using the model of a fast-moving concentrated source with an ellipsoid crystallization front. The width of the secondary elements of the dendrites in the crystallized slab was numerically estimated as 0.2 nm at the center point of the circle heat spot, and the two types of dendrites were predicted in the specimen: the dendrites from 0.2 to approximately 50 nm and from approximately 0.1 to 0.3 μm in width of the secondary elements. The results were found to be in good accordance with the measured experimental values of the dendritic structure geometry parameters.
Since nowadays the economy of the Russian Federation depends greatly on export of these mineral deposits, it is necessary to start development and exploitation of new deposits in a short space of time. Thereby, it is necessary to start rapidly development and sophistication of the technologies for reconditioning, repair and enhancement of performance characteristics of the drilling equipment used for extraction of mineral deposits, particularly, in the Arctic zone. The list of domestic manufacturers of drilling equipment is shown. Domestic laser installations for such technologies are described in the article.
Direct energy deposition is a reliable additive manufacturing method of producing components with highly sophisticated geometry from a single material or combination of different materials with high manufacturing freedom and efficiency. The assembly operations are not required after the direct energy deposition: such complex parts as a rocket combustion chamber, a nuclear reactor element, a heat exchanger, and so on, could be fabricated layer-by-layer during one technological step. Promising applications are associated with Cu-Fe system laser deposited functionally graded components, which allow combining good oxidation resistivity, antifrictionality, thermal, and electrical conductivity of copper with mechanical strength, processability, and corrosion resistance of stainless steel. The main issue, which appears in the case of laser deposition of such materials, is internal stresses caused by significant inequality of physical properties of copper/bronze and steel, their limited miscibility, forming of brittle phases at the interface, and complexity of variation of mechanical and physical properties of the resulted alloy. The mentioned factors could cause various cracking in resulted parts. Specific techniques such as ultrasonic assistance, implementation of the external magnetic field, and post-treatment (hot isostatic pressing, machining), could be suggested to improve the quality of laser deposited Cu-Fe system functionally graded materials.
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