Fabrication of Cu-W Nanocomposites by Integration of Self-Propagating High-Temperature Synthesis and Hot Explosive Consolidation Technologies

A Peikrishvili,B Godibadze,D.R Lesuer,E.Sh Chagelishvili,G Mamniashvili,H.V Kirakosyan,L.S Abovyan,M Gutierrez,M.K Zakaryan,S.L Kharatyan,S.V Aydinyan

doi:10.18321/ectj763

Abstract

Manufacturing W-Cu composite nanopowders was performed via joint reduction of CuO and WO3 oxides with various ratios (W:Cu = 2:1, 1:1, 1:3, 1:13.5) using combined Mg–C reducer. Combustion synthesis was used to synthesize homogeneous composite powders of W-Cu and hot explosive consolidation (HEC) technique was utilized to fabricate dense compacts from ultrafine structured W-Cu powders. Compact samples obtained from nanometer sized SHS powders demonstrated weak relation between the susceptibility and the applied magnetic field in comparison with the W and Cu containing micrometer grain size of metals. The density, microstructural uniformity and mechanical properties of SHS&HEC prepared samples were also evaluated. Internal friction (Q-1) and Young modulus (E) of fabricated composites studied for all samples indicated that the temperature 1000 °С is optimal for full annealing of microscopic defects of structure and internal stresses. Improved characteristics for Young modulus and internal friction were obtained for the W:Cu = 1:13.5 composite. According to microhardness measurement results, W-Cu nanopowders obtained by SHS method and compacted by HEC technology were characterized by enhanced (up to 85%) microhardness.

Highlights

The combination of two immiscible tungsten and copper phases in a W-Cu composite generates a pseudo-alloy which may cover the major needs of an advancing electronic technology and engineering
To optimize the reduction conditions according to ambient gas pressure and initial mixture composition, as well as to provide combined and accomplished reduction of CuO and WO3 oxides the software package ISMAN-THERMO developed for multi-component systems was used [30]
The results indicated that for the W/Cu composites the temperature 1000 °С is optimal for full annealing of microscopic defects of structure and internal stresses

Summary

Introduction

The combination of two immiscible tungsten and copper phases in a W-Cu composite generates a pseudo-alloy which may cover the major needs of an advancing electronic technology and engineering. 302 Fabrication of Cu-W Nanocomposites by Integration of Self-Propagating High-Temperature Synthesis refinement leads to an increase of interfaces between phases, improves the strength of materials, inevitably deteriorates the sintering process and electrical properties. A novel strategy based on self-propagating high-temperature synthesis (SHS) or combustion synthesis (CS) method for the preparation of fine Mo-Cu and W-Cu composite powders was reported. It involves the joint reduction of CuO and WO3 (MoO3) oxides by using combined Mg+C reducer [21,22,23,24]. The density, microstructural uniformity and mechanical properties of SHS&HEC prepared samples were evaluated

Experimental

Results and discussion

Combustion synthesis and characterization of W-Cu powders

HEC consolidation and characterization of compact samples

Conclusions