Synthesis and characterization of W-Cu nanocomposites developed by mechanical alloying

摘要

In the present investigation, attempts have been made to synthesize W-Cu nanocomposites by mechanical alloying (MA) and the results show that MA is a very good processing technique in making these nanocomposites. Elemental tungsten and copper are also milled. Characterization techniques like XRD, TEM and SEM have been used to study the crystallite size, r.m.s. strain and their morphology changes on milling. Crystallite size of tungsten was found to 15 nm and that of copper as 40 nm after 20 h of milling. Tungsten being brittle has lower crystallite sizes than copper on milling. Copper being ductile has good cushioning effect and tungsten crystallite sizes are relatively higher in the as-milled W-Cu samples when the fraction of copper is higher in W-Cu system. Elemental tungsten, elemental copper and W-Cu nanocomposites obtained after milling for 20 h were subjected to annealing at 400, 600, and 800℃ for 2 h and the phase transformation in these powders was studied.