Cu °C [10, 11]. In the other hands

Cu alloys are widely used in industrial applications
because of their excellent properties such as high thermal and electrical
conductivity, heat resistance, ablation resistance and high strength. Cu-W
alloys are extensively used as sweat cooling, contact alloy, electrical contact
and electronic packaging materials 1-8. W
has high density, melting point and hardness than that of Mo that eliminate the
application of Cu-W alloy. Mo is a good candidate to be replaced with W and
Mo-Cu alloys are also easy to sinter and process than W-Cu alloy.

In the Mo-Cu system the heat of mixing is positive (+18
kJ/mole) 9 there is a signi?cant
difference in melting points and lactic parameter of copper (TCu =
1083 °C, aCu= 0.361 nm) and molybdenum (TMo = 2625 °C, aMo=
0.314 nm) which the solid solubility of Mo in Cu is 0.5 wt.% at 1100 °C 10, 11.
In the other hands Mo-Cu alloys is immiscible in both solid and liquid states
and do not form any alloy using conventional equilibrium methods such as
casting or liquid metallurgy 12. The extension of solid
solubility beyond the equilibrium values could be achieved by non-equilibrium
methods, such as rapid solidi?cation process, vapor deposition, laser
processing, sputtering, ion beam mixing, and mechanical alloying (MA) of
elements. Among mentioned methods MA is a simple method due to its ability to
increase solid solubility at ambient temperature and this process could achieve
a larger solid solubility extension. Plastic deformation, fracture and cold
welding of particles, during MA of the powder mixture, leading to a continuous
microstructure re?nement of particles and increasing specific surface area. Stacking
faults, vacancy and dislocation arrays increased in the particles grain during
the process of mechanical milling of the powder mixtures and the cold welding
between the different particles minimizes the diffusion distance between atoms
and solubility of elements increased in the nanostructured particles 13, 14.

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Many researches have been focused on synthesis Mo-Cu
alloys with MA processes which result fine grain alloys with homogeneous
microstructures and excellent properties 2, 14-19.
In the fabrication of Mo-Cu alloys with MA process, starting materials are
often mixed together elementally in the ball milling system 16, 19, 20.
Sun et. al synthesized novel core shell Cu-Mo nanoparticles via a simple ball-milling of MoO3-CuO mixture
and subsequent hydrogen reduction process 12. In some other works
Mo-Cu fabricated with combustion reaction using Al as reducing agent 21. Magnesio-thermal
reduction of MoO3-CuO mixture oxides was reported to be high caloric
process which proceeds in combustion mode 11. In the case of using
reducing metals such as Al, Mg, Na or Ca, that is most of the time challenging
task to purify nanocrystalline powders from undesired byproducts. The advantage
of using graphite as reducing agent is that CO2 gas is the byproduct
that are removed simultaneously during the reaction. Lubricating properties of
graphite also prevents the particles from accumulating during milling and leads
to the formation of smaller particles. Previous studies have shown the
formation of nanocrystalline metallic powders via mechano-chemical reduction of
NiO 22, V2O5 23, CuO 24, 25
MoO3 26 with carbon and the
effect of milling processing on the reduction of metal oxides were reported. In this paper, nano-crystalline Mo-Cu alloy has been
synthesized via co-reduction of molybdenum trioxide (MoO3) and
copper oxide (CuO) with graphite using high energy planetary ball milling and
subsequent heat treatment


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