The peculiarities of the fine structure of Al–Si–Ni aluminum-matrix composite with a low thermal coefficient of linear expansion, mechanically activated with the addition of nanoscale reduced graphene oxide (RGO), is investigated. The structure is studied by X-ray diffraction analysis, scanning, transmission and high-resolution transmission electron microscopy. The presence of quasi-graphene layers on the surface of aluminum and silicon particles is detected and it is shown that this shell protects them from clumping upon mechanical alloying, which significantly increases the manufacturability of the process of mechanical activation and subsequent compaction. Thus, it is possible to obtain composite materials with a homogeneous structure and higher physical properties (the use of RGO instead of electrode graphite reduces the thermal coefficient of linear expansion (TCLE) of the composite by 10%).

Results of an investigation into the development of the composition and fabrication technology of compact billets of the aluminum powder composite material based on the Al–Si–Ni system for space-rocket hardware are presented. The composite production was performed as follows: initially the powder of the matrix alloy is prepared by gas sputtering, and then a mixture of the matrix alloy powder and alloying dispersed additives is subjected to mechanical alloying in high-energy apparatuses. The method of degassing the mechanically alloyed composition in a thin layer (in order to exclude material ejection from a container when degassing a larger volume of powder) and process regimes of composition compaction are developed using the unique equipment available at OAO Kompozit (Korolev, Moscow oblast)—a vacuum press. Using this technology, cylindrical briquettes up to 100 mm in diameter and up to 120 mm in height are fabricated. Newly developed and patented Kompal-301 composite material has substantial advantages over SAS-1-50 power alloy applied for similar purposes. Its thermal linear expansion coefficient is lower by a factor of 1.5, while the precision limit of elasticity is higher by a factor of 2–3 upon similar strength characteristics. The final structure of a compact briquette is a matrix in which dispersed particles of excess silicon are distributed rather uniformly against the background of the aluminum solid solution. Coarser isolated silicon particles are met in separate regions of the structure. Unfortunately, they are the cause of low plasticity of briquettes, which prevents the formation of semifinished products by plastic deformation; however, such low plasticity does not immediately negatively affect the fabrication of the briquettes themselves.

The paper provides the results of alloy development investigation and technology of making compact billets of the Al-Si-Ni-based composite for aerospace equipment components. Composite production included several stages: first, matrix powder was produced by gas atomization and then matrix powder with disperse alloying additives was mechanically alloyed in high-energy machines. The vacuum press, unique equipment located at OJSC «Kompozit» (Korolyov, Moscow region, Russia), was used to develop and test the technology of mechanically alloyed composite degassing in a thin layer (to eliminate material ejection from the container when degassing a large volume of powder) as well as to tryout composite compaction process modes. Cylindrical billets up to 100 mm in diameter and up to 120 mm in height were obtained based on this technology. Kompal-301, a newly developed and patented composite, has significant advantages compared to the SAS-1-50 sintered aluminum alloy due to 1,5 times lower thermal coefficient of linear expansion and 2–3 times higher precision elastic limit with the same density values. The compacted billet has a resulting matrix structure with disperse silicon excess particles distributed quite uniformly over the aluminum solid solution. There are some larger isolated silicon particles in certain structure areas. Unfortunately, they cause lower billet ductility so it is impossible to produce semi-finished products by plastic deformation. However, such a low ductility has no negative effect on the billet production itself.

The structure and mechanical properties of a two-phase Kh65N33V2FT alloy has been studied after tests at room and high temperatures. The morphology of the main phases, namely, solid solutions of nickel in chromium (α) and chromium in nickel (γ), is changed depending on temperature. The lattice parameters of the main phases have been determined. The main mechanism of deformation for this alloy is shown to be grain-boundary sliding. Bulk and grain-boundary diffusion creep and self-regulating diffusion-viscous flow is possible in the γ phase during high-temperature deformation. The heat resistance of this alloy is restricted to 1000°C because of the formation of a γ-phase percolation cluster.

The segregation energies of B, Si, P, Cr, Ni, Zr, and Mg on the special grain boundary (GB) Σ5 (210)[100] and on the open (210) surface of aluminum have been determined and the GB splitting energy has been calculated by the density functional theory methods. It has been shown that all elements listed above enrich the GB; for B, Si, P, Cr, Ni and Zr, Mg, interstitial and substitutional sites are preferred, respectively. The effect of alloying elements on the GB binding has been estimated using the parameter η equal to the change in the fracture work of the aluminum GB when adding alloying element atoms. From the viewpoint of strengthening the GB binding forces, Zr, Cr, Ni, and Mg are efficient, Si and B are neutral and phosphorus weakens GBs.