High-Temperature Stability of a Nanostructured Cu-Al₂O₃ Alloy

Abstract

A nanostructured oxide dispersion strengthened (ODS) copper alloy powder, containing an alumina dispersion (about 1% vol.) was prepared by mechanical alloying and subsequently consolidated by hot extrusion. The high temperature stability of the nanostructured and consolidated powders was studied. The stability of the nanostructure was checked with 1 hour heat treatments in the range 400-800ºC. Powders were vacuum encapsulated in copper cans and extruded at temperatures in the range 500-600ºC. The crystallite size of both the as-milled and the heat treated powders was determined with X-ray diffraction (XRD). The line broadening was used to calculate grain (crystallite) size. Two methods were used: the Scherrer equation (SE) and the Williamson-Hall plot (WH). The microstructures of both loose powders and extruded powders were characterised with Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The mechanical properties were assessed with microhardness measurements. The results obtained via XRD with both methods are within the same order of magnitude. A reasonable agreement is also obtained with SEM and TEM observations. The X-ray determination of grain size and the microhardness measurements indicate negligible grain coarsening up to 800ºC. On the other hand, the consolidated powders showed lower hardness values than those of the as-milled and annealed powders. The nanostructured copper alloy studied shows good thermal stability at temperatures up to 800ºC.

Transmission electron microscopy study of copper–carbon nanocomposite

“…[4][5][6][7][8] In effect, the variation in lattice parameter obtained from the Cu210C (at.-%) mixture after milling for 36 ks (Da Cu 50 . 00011 nm) (Ref.…”

“…The presence of amorphous carbon clusters explains the apparently modest increase in lattice parameter reported by several authors in mechanically alloyed Cu2C systems. [4][5][6][7][8] In effect, the variation in lattice parameter obtained from the Cu210C (at.-%) mixture after milling for 36 ks (Da Cu 50 . 00011 nm) (Ref.…”

Effect of Al2O3 Content on Electrical Breakdown Properties of Al2O3/Cu Composite

“…Most studies focus on the microstructure, physical and electrical properties of Al 2 O 3 /Cu composite (Ref [5][6][7][8][9][10][11][12][13][14], but no literatures on the relationship between microstructure and arc erosion behavior of Al 2 O 3 /Cu composite have been reported. In this investigation, Al 2 O 3 /Cu composite was prepared by external addition of Al 2 O 3 and the effect of Al 2 O 3 content on hardness, electrical conductivity, breakdown strength, chopping current and arc life was studied.…”

Influence of Al2O3 reinforcement on precipitation kinetic of Cu–Cr nanocomposite

“…Copper matrix composites reinforced with metallic precipitates, i.e. in situ composites, or ceramic particles, like Al2O3, ZrO2 or TiC [1], [2] and [3], have received a great deal of attention in recent years. These composites possess advantageous properties, in particular, high electrical and thermal conductivity and good mechanical properties.…”