**1. Introduction**

The development of the basic principles for creating new composite materials is undoubtedly an important task of modern materials science. The demand for such materials is due to the possibility of combining enhanced mechanical properties (strength, wear resistance, crack resistance, sti ffness, heat resistance and fatigue limit) [1–3].

Along with natural composites (mollusk shells, bones, wood), there are man-made artificial composites based on polymer, metal and ceramic matrices reinforced with fibers or filled with disperse particles. Such variety allows one to permanently expand the application field for composite materials.

Comprehensive studies have shown that enhanced mechanical properties can be achieved in multilayer composite systems consisting of amorphous and crystalline materials [4–9]. In addition, metallic materials with discrete structure constituents of nanoscale range can combine increased ductility with su fficiently high strength characteristics. This di ffers amorphous-nanocrystalline composites and advanced nanocrystalline materials from conventional structural materials produced by conventional technologies. Moreover, the controlled transformation of amorphous into nanocrystalline state makes it possible to successfully manage the functional properties of amorphous-nanocrystalline composites [10–13]. There is a well-known Ulitovsky-Taylor method for manufacturing one-dimensional composite material consisting of a high-strength magnetically soft metal base with an amorphous and/or nanocrystalline structure and an outer glass shell [14,15]. Another way to obtain amorphous-nanocrystalline composites is to decrease the critical rate of melt cooling upon manufacture of amorphous alloys (AA) by melt spinning method [16]. Heat treatment of AA at controlled temperature and time parameters initiates the nucleation and growth of nanocrystals, i.e., the formation of a composite material with an amorphous matrix [17–19]. It is possible to modify the AA surface by laser for the manufacture of "sandwich" amorphous-nanocrystalline composites and gradient structures with amorphous-nanocrystalline components [20–22]. The composite consisting of an amorphous phase with a nanocrystalline filler can surpass fully amorphous or fully crystalline analogs in the combination of properties [23–26].

As is known, high-pressure torsion (HPT) allows one to create new structure states by the consolidation of small fractions, due to the occurrence of the "crystalline-amorphous" phase transitions in the material [27–29]. In the framework of the present work, the idea arose to use the possibilities of severe plastic deformation (SPD) in a Bridgman chamber for the preparation of layered amorphous-nanocrystalline composites. We used two fundamentally different methodological techniques (Figure 1):

**Figure 1.** (**a**) Severe plastic deformation (SPD) scheme for the composite preparation: Bridgman chamber consisting of immobile *1* and movable *2* anvils, carbide inserts *3*, sample *4* of alternating amorphous alloys (AA) ribbons (**b**) or the Cu-Nb nanolaminate (**c**).

(1) HPT consolidation of AA melt spun ribbons differing in chemical compositions and mechanical properties [30];

(2) the use of Bridgman chamber for deformation processing of nanocrystalline Cu-Nb laminates prepared by multiple pack rolling (MPR) [31].

AA, due to the presence of a homogeneous structure and the absence of defects (dislocations and grain boundaries), demonstrate a higher level of mechanical properties that exceeds the level of properties achieved in the crystalline alloys. However, these materials have a serious flaw—the absence of tensile plasticity and low plastic deformation under compressive loads—which makes them prone to brittle fracture, and, accordingly, greatly limits their possible application. Structure changing during crystallization is an important aspect of AA research, since one of the ways to increase the ductility of AA is the formation of composite structure "glass-crystal".

Ternary AA of the Fe-Ni-B system (for example, Fe58Ni25B17, Fe53.3Ni26.5B20.2, Fe50Ni33B17) are model alloys. External actions on the Fe-Ni-B AA cause precipitation of a Fe-Ni nanocrystalline phase, which can vary in crystal lattice types (BCC, FCC) depending on the ratio between the iron and nickel concentrations. Thus, it possible to establish the effect of the type crystal lattice of nanocrystals on the mechanical behavior of materials with an amorphous-nanocrystalline structure. In addition, partial crystallization can favor changes in their soft magnetic characteristics.

The Co-Fe-Cr-Si-B AA is related to corrosion resistant materials and exhibits a high electrical resistivity, low magnetization-reversal loss over a wide frequency range, low coercive force and resistance to impacts and vibrations. The high-cobalt amorphous alloys are characterized by near-zero saturation magnetostriction (λ*s* ≤ <sup>10</sup>−7) and very high magnetic permeability. For this reason, such AA show promise as materials for magnetic shields [23].

Multilayer Cu-Nb laminates with nanoscale layer thicknesses are typical representatives of nanostructured composite materials with a unique combination of properties: good ductility, high electrical conductivity of copper and superconductivity of niobium. The combination of the copper-niobium system is demanded, and is actively used in the manufacture of microwires in resonant power transmission systems, inductors for magnetic pulse stamping and welding, foils in electronics for flexible printed circuits; in large magnetic systems at 50–100 T and in high-field cryogenic synchronizers of industrial frequency.
