Effects of milling time on the properties of in-situ binary niobium-titanium-carbide reinforced Cu based composite

Authors: Trần Đức Huy, Lê Minh Hải*


Mechanical alloying was used to synthesize in-situ a copper based composite reinforced by binary niobium-titanium-carbide from Cu, Nb, Ti and grphite powder mixture. The nominal composition correponded to Cu-30 vol.% (Nb-Ti)C. XRD showed that (Nb, Ti)C were not formed in the as-milled powder after 5 hours of milling but was precipitated with a subsequent sintering at 900oC. Milling time have showed a great influence on both mechanical and physical properties of the sintered composite pellets. Increasing milling time leads to an increase of the microhardness of the composite due to a higher degree of deformation that enhanced hardening. On the other hand, the electrical conductivity decreases considerably when the milling time increases. This phenomenon could be atrributed to the increase of density of grain boundaries, which acts as a centre of electron scattering, with milling time.