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New Material Hybrids With Helical Inner Architecture: Fundamentals And Technology

Periodic Reporting for period 1 - HybridMat (New Material Hybrids With Helical Inner Architecture: Fundamentals And Technology)

Reporting period: 2018-02-01 to 2020-01-31

Hybrid Materials for Energy Applications

This research aimed on fundamental study of physical mechanisms triggered by simultaneous mixing and nanostructuring of immiscible metals by severe shear while producing new types of hybrid materials with simultaneously improved strength and electrical conductivity.

Severe Plastic Deformation was used for production of multicomponent materials to obtain properties not found in individual conventional materials. The ‘architecturing’ of the hybrid structure with consideration of the interface bond and enhanced interdiffusion enhanced combination of both strength and conductivity.
This project is expected to have practical applications, it addressed the nanostructured high-strength electrical conductor cables for efficient energy transmission.

It is important for society as it reduces the price of electricity for the end users, households and businesses alike.

The Objectives of the Project:

The objectives of the project consisted of technological innovations and fundamental study advancing the
current state of knowledge. All six objectives were successfully fulfilled.
The work performed is covered by next 2 publications in open access Journals with the first one being the main one:

1. R. Lapovok, Architectured Hybrid conductors: Aluminium with embedded copper helix, Materials & Design, (2019), (

Abstract: This study is inspired by the potential of application-designed aluminium-copper conductors. This work combines
recently discovered advantages of hybrids with one constituent having a helical architecture with the benefits
provided by severe plastic deformation (SPD)methods. The hybrids are made by embedding copper helixes
in melted aluminium and subjecting cast hybrid ingots to different SPD techniques. The electrical conductivity,
microstructure features and strength of the produced samples are discussed in relation to effect of SPD and annealing
on both constituents and an interface zone formed during the hybrids' production. Itwas shown that between
all processing techniques the reciprocal extrusion (RE) has the great potential for production of
lightweight conductors with high conductivity and enhanced strength. A new model describing the effective
electrical conductivity of hybrid samples, consisting of an aluminium matrix with an embedded copper helix
and intermetallic containing interface, is developed and justified by experimental data.
The model is shown to be instrumental for analysis of the effect of the helix's parameters and interfacewidth on effective conductivity of
the hybrid samples and could be used for optimal design of hybrid conductors.

2. R. Lapovok, Effect of Severe Plastic Deformation on the Conductivity and Strength of Copper-Clad Aluminium
Conductors, Metals, Special Issue Severe Plastic Deformation and Thermomechanical Processing: Nanostructuring and Properties, 9:9 (2019), Article Number: 960.

Abstract: Aluminium rods with dierent copper sheath thicknesses were processed by severe plastic
deformation at room temperature and then annealed, to join the constituent metals and produce a
nanocrystalline microstructure. A study of the eects of the deformation parameters, copper cladding
thickness and annealing temperature on the electrical conductivity and hardness of the conductors
is reported. It is shown that an interface forms between constituents because of intermixing in
the course of severe shear deformation under high hydrostatic pressure and diusion during the
subsequent annealing. The eective conductivity of the aluminium copper-clad conductor dropped
after deformation, but was recovered during annealing, especially during short annealing at 200 C,
to a level exceeding the theoretically predicted one. In addition, the annealing resulted in increased
hardness at the interface and copper sheath.
The project raised a public awareness of possible saving on cost of electricity by reducing the electric power transmission and distribution losses include losses in transmission between
sources of supply and points of distribution to industrial and residential consumers. It was proven by theory and experiments that by using of hybrid Al/Cu conductors these losses could be reduced
due to decrease of the electrical resistance of the transmitting cables and the deflection of cables between conductor support structures.
The technology suggested is based on nanostructuring of aluminium alloy with embedded copper helical reinforcement, which resulted in double increase of strength and about 40%
decreases in the electrical resistance of hybrid material.
The social-economic impact consist of reduction the price on electricity for the end-users and implies further contribution to the save environment.
strength-conductivity relation for developed hybrid conductors