Pengaruh Variasi Suhu Kompaksi terhadap Struktur Mikro, Sifat Mekanis, dan Konduktivitas Listrik Paduan (CuNi)-3wt.%Fe dengan Metode Metalurgi Serbuk

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.