| dc.description.abstract | Copper is commonly used as the main electrode material for EDM machine.
This element known had excellent electrical conductivity, but overall also lacks in
mechanical properties. Improvements in mechanical properties are carried out by
increasing the pressure or temperature of sintering, using warm compaction during
the compaction process or combining with other elements to improve the required
characteristics. The optimum temperature for the warm compaction process is
generally in the range of 100-200oC. This study aims to analyze the effect of
variations on warm compaction temperature in (CuNi)-3wt.%Fe alloys on
microstructure, mechanical properties, and electrical conductivity using powder
metallurgy method. The materials used are copper (Cu), nickel (Ni), and iron (Fe)
with a composition ratio of 87:10:3 wt.%. The powder mixing process used a
horizontal ball milling machine with a rotation speed of 300 rpm for 2 hours, then
putted into a mold for a compaction process with a pressure of 250 MPa for 15
minutes without temperature and with a compaction temperature of 150, 200, and
250oC. The sintering process is carried out for 60 minutes at a temperature of 770oC
using electric muffle furnance. The tests carried out include tests of density,
hardness, bending, electrical conductivity, and microstructure. The highest value
obtained at a temperature of 250oC is a density of 7.71 gr/cm3, hardness of 63.7
VHN and electrical conductivity of 78.97% IACS. Porosity decreases and a few of
solid solution phase is formed between Cu and Ni, but oxidation is increased. The
highest bending test’s yield strength obtained at 227.16 MPa at 150oC and slowly
decreased to the lowest at 250oC at 184.30 MPa. Higher temperatures caused more
oxidation to form so the yield strength decreases. It can be concluded that increasing
the compaction temperature in the optimum temperature range can improve
mechanical properties without significantly reducing electrical conductivity. | en_US |
