Pengaruh Variasi Tekanan Warm Compaction Terhadap Struktur Mikro, Sifat Mekanis dan Konduktivitas Listrik Paduan (CuNi)-5wt%W Menggunakan Teknik Metalurgi Serbuk

Abstract

Electrical Discharge Machining (EDM) process is a material machining process that creates an electrical spark in the gap between the cathode (bit) and the workpiece (anode) . Copper is a single element commonly used as an electrode in electrical discharge machining (EDM) machines. Copper is known as a material that has good electrical conductivity but poor mechanical properties at high temperatures. To increase the lifetime of the electrodes, the mechanical properties of EDM electrodes need to be improved. This improvement can be achieved in several ways, including the addition of metal alloying elements, increasing the compaction pressure, and using a suitable sintering temperature in the powder metallurgy process. The aim of this research is to determine the influence of hot compaction pressure on an alloy (CuNi) -5 wt% W on the mechanical properties and electrical conductivity of EDM electrodes. The materials used in this research were copper (Cu), nickel (Ni), and tungsten (W) powders. The powder mixing process uses a horizontal ball mill which is carried out at a speed of 300 rpm for 2 hours. The mixed powder is weighed and put into a mold to compact it with variations of compaction pressure of 190 MPa, 220 MPa and 250 MPa for 15 minutes at a temperature of 150 °C to produce a green compact, followed by a sintering process at a temperature of 770 °C for 120 minutes in an electric muffle furnace . Tests conducted include density tests, Vickers hardness tests, compression tests, electrical conductivity tests and microstructure tests of alloy (CuNi)-5 wt%W. The best value for each test was obtained at a warm compaction pressure variation of 250 MPa, namely 7.53 g/cm3 for density test, 88.2 VHN for Vickers test , 214.855 MPa for compression test, 60.29%IACS for electrical conductivity test, etc. Results of microstructure tests show that increasing compaction pressure increases the solid solution phase of the alloy and can decrease the porosity of the alloy