Novel drawing system approach to manufacture performant commercially pure aluminium fine wires

Serafino Caruso,Giuseppina Ambrogio

doi:10.1007/s00170-021-08005-2

Abstract

Due to its electro-mechanical properties, commercially pure aluminium wires have attracted the interest of automotive industry representing a functional and efficient economic solution to reduce vehicle’s weight leading to the diminishing of energy consumption and emissions in today’s society. However, to consolidate its use in this sector and in new market realities, it is necessary to increase the flexibility of the aluminium conductor wires, consenting their installation in very small spaces and with high curvatures, avoiding any failure and electrical conductivity decrease. Thus, the evolution of microstructure and service performance needs to be investigated and controlled to improve the service safety. The present research shows a new approach to continuously manufacture efficient long wires with smaller diameters and fine grains at room temperature. It is studied the strengthening effects (yield and tensile strength, plasticity, hardness), the electrical conductivity, and the microstructural changes of commercial 1370 pure aluminium (99.7% Al) when traditional wire drawing process is combined with equal channel angular drawing (ECAD) technique. The results of this proposed procedure of deformation “drawing-ECAD-drawing” show an evident benefit, compared to the classic technology of production of aluminium wire, obtaining fine grain structure product with superior mechanical strength and not influenced electrical conductivity. The proposed manufacturing approach leads to fine wires enhancing the material mechanical properties by microstructural evolution (i.e. grain size reduction) avoiding the traditional post manufacturing thermal treatments requiring a high amount of energy and time and careful steps.

Highlights

Pure aluminium wire (CPAW) is considered as an important conductor line for transmitting electric power due to its high corrosion resistance, good electrical conductivity and light weight [1,2,3]
The results show the distribution of the plastic deformation mode, texture evolution, and grain size on the wire cross section, clarifying the relationship between microstructure evolution and stress profile at each drawing pass
With the aim (i) to give a further contribution in this direction investigating and analysing the beneficial influence of the microstructural changes to the enhancement of the material properties by recrystallization, (ii) to extend the knowledge of the effectiveness of the severe plastic deformation (SPD) technique in controlling grain size evolution, (iii) to promote aluminium as a valid alternative to copper production of electrical conductors, and (iv) to analyse a new approach to the conventional drawing manufacturing system, in this paper a mechanical, electrical, and microstructural analysis was conducted on Commercially pure aluminium wire (CPAW) by interposing equal channel angular drawing (ECAD) method in the traditional wire drawing process at room temperature

Summary

Introduction

Pure aluminium wire (CPAW) is considered as an important conductor line for transmitting electric power due to its high corrosion resistance, good electrical conductivity and light weight [1,2,3]. With the aim (i) to give a further contribution in this direction investigating and analysing the beneficial influence of the microstructural changes to the enhancement of the material properties by recrystallization, (ii) to extend the knowledge of the effectiveness of the SPD technique in controlling grain size evolution, (iii) to promote aluminium as a valid alternative to copper production of electrical conductors (i.e. copper: more expensive, heavier and with a greater environmental impact), and (iv) to analyse a new approach to the conventional drawing manufacturing system, in this paper a mechanical, electrical, and microstructural analysis was conducted on CPAWs by interposing ECAD method in the traditional wire drawing process at room temperature. The importance of the two investigated empirical models is based on the evaluation of the microstructural change (i.e. grain size refinement and dislocation evolution) on the material behaviour

Material and methods

Tensile test and fatigue analysis

Conclusions

Data availability Not applicable