Consolidation of Copper-Copper Nitride Nanocomposite Powders via Warm Extrusion

摘要

Copper nitride films prepared by sputtering have applications such as optical data storage material, insulation barriers in micro electronic devices and coatings for mechanical applications. The present study examines nanocomposites prepared by mechanical alloying of copper with copper nitride under nitrogen atmosphere, at room temperature, in order to establish a comparison with properties of Cu-N sputtered films. The powders were consolidated into bulk samples via warm extrusion at temperatures ranging from 300 to 500°C (0.42-0.64 T_f) after encapsulation without degassing. The as-milled powders and the extruded materials were studied using X-ray diffraction, optical microscopy, scanning and transmission electron microscopy and microhardness measurements. Also, the TEM observation of the extruded sample indicates a mean grain size of about 50 nm. This evidences a higher thermal stability of the as-milled powders and the advantage of using a fast consolidation process, at a relatively low temperature. Therefore, the consolidated material did not show the dramatic softening associated with recrystallization. The consolidation of nanostructured copper-copper nitride composite powders via warm extrusion, without major grain coarsening, was demonstrated.