FORMATION OF INHOMOGENEITIES AND DEFECTS IN THE STRUCTURE OF COMPOSITE MATERIALS AND FUNCTIONAL-GRADIENT BIMETALLIC COMPONENTS PRODUCED BY WIRE-BASED ELECTRON-BEAM ADDITIVE MANUFACTURING

The paper presents the results of studies of the formation of defects and inhomogeneities in composites with a metal matrix and bimetallic products based on dissimilar metals and alloys when obtained by wire additive electron-beam technology. The main defects in the production of composites and bimetallic elements are pores, micro- and macro-cracks, as well as stratifications of different types. From the inhomogeneities of the structure, it is mainly possible to distinguish the resulting agglomerates of powder particles introduced simultaneously with the wire feed, large fragments of different components of the structure and the resulting large intermetallic structures. These structural elements can have a negative influence on the strength properties of materials, cause a sharp drop in mechanical properties. The main reasons for the formation of defects of different types are non-compliance with the optimal values of the process parameters, excess of the optimal concentration of components, significant differences in the density and melting temperature of the structural components. Despite the presence of defects, the modification of the process of feeding the material into the printing zone makes it possible to achieve a relatively homogeneous structure of different composite materials and high values of mechanical properties.

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