Features of the formation of thermophysical properties of functionally graded bimetallic compositions formed by additive technologies

Modern additive technologies for the manufacture of bimetallic compositions are considered with an emphasis on their effect on thermophysical properties, particularly, thermal conductivity. The main attention is paid to methods of selective laser melting (SLM), directed energy deposition (DED), wire arc additive manufacturing (WAAM), as well as alternative approaches: electron beam melting, cold gas dynamic spraying and extrusion of metal polymer composites. It is emphasized that additive processes lead to anisotropy of the microstructure and, as a result, to directional thermal conductivity. For example, the Cu – 2.4 Ni – 0.7 Si alloy has a thermal conductivity along the Z axis three times higher than in the transverse direction. The analysis of key problems such as the formation of cracks and pores at the interface, thermal stresses, incompatibility of the coefficients of thermal expansion, as well as shrinkage during cooling or sintering is performed. Solutions such as the use of functionally graded materials (FGM), intermediate layers, optimization of energy efficiency parameters and material supply strategies are proposed. A discussion of interface quality control methods and requirements of current standards is presented (GOST R 59930–2021, NASA MSFCSTD-3716, ISO/ASTM TR 52905). The article highlights the prospects of additive bimetals for heat exchanging and current conducting elements under the condition of integrated control of the interface structure and properties.This work was carried out with the support of the Ministry of Science and Higher Education of the Russian Federation under state assignment No. FSFF-2023-0006.