A. Benghalem et Dg. Morris, MICROSTRUCTURE AND MECHANICAL-PROPERTIES OF CONCENTRATED COPPER NIOBIUM ALLOYS PREPARED BY MECHANICAL ALLOYING, Materials science & engineering. A, Structural materials: properties, microstructure and processing, 161(2), 1993, pp. 255-266
Mechanical alloying was used to prepare powders of copper-niobium allo
ys containing between 10% and 28% by volume of niobium which were subs
equently consolidated by hot compaction or extrusion. Materials contai
ning higher niobium contents are stronger in the powder state and afte
r annealing at lower temperatures but are less stable at high temperat
ures than the more dilute materials examined here and these concentrat
ed alloys soften faster during high temperature annealing. Strengtheni
ng in the powder state is affected by the extensive work hardening int
roduced by the milling process but after consolidation the strength is
mostly determined by Orowan-type dislocation pinning by fine particle
s. Milling powders, even for extended time periods, is not able to ref
ine all the added niobium to the optimum nanometre scale and the remai
ning coarser niobium leads to faster microstructural coarsening during
high temperature annealing.