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Grain structure and mechanical properties of the commercially pure copper and Cu-Al hybrid materials processed by the High Pressure Torsion Extrusion

Wednesday (26.09.2018)
17:45 - 18:00 S1/01 - A1
Part of:

A comparative analysis of the microstructure and mechanical properties of commercially pure copper and Cu-Al hybrid samples processed by the High Pressure Torsion Extrusion (HPTE), a novel technique of severe plastic deformation (SPD) had been performed. The new HPTE technique allows to achieve large strains (up to 30) during just one pass in large-scale rod specimens with the diameter of 10 mm and the length of 35 mm. Figure 1 schematically illustrates the HPTE process along the extrusion direction with composite Cu samples with embedded Al wires before and after one HPTE pass with translation velocity 3 mm/min and angle velocity 1 mm/min.

Room temperature mechanical tests, optical and scanning electron microscopy microstructure investigations of the as-processed samples were performed.

In pure copper a gradient structure of different types: coarse-grained, fine-grained and ultrafine-grained depending on HPTE regimes was detected. Applied HPTE regimes provided strong grain refinement in pure copper from 20 – 30 to the 0.3 – 0.4 micrometers.

In hybrid Cu-Al samples the variation of the shape of Al wires was monitored. It was found that Al wires got thinned as a result of HPTE processing, upon that wire thickness depends on its distance from the sample center. In the middle-radius areas initially 1 mm diameter wires were thinned to the tapes with the thickness of 20-30 micrometers, whereas in the edge areas their thickness was 2-3 micrometers, which reflects the strain gradient at HPTE. The influence of the HPTE regimes on the microstructure and mechanical properties of gradient and hybrid samples will be discussed.

Dayan Nugmanov
Karlsruhe Institute of Technology (KIT)
Additional Authors:
  • Dr. Roman Kulagin
    Karlsruhe Institute of Technology (KIT)
  • Dr. Yulia Ivanisenko
    Karlsruhe Institute of Technology (KIT)
  • Prof. Dr. Horst Hahn
    Karlsruhe Institute of Technology (KIT)