Effect of sintered electrode on microhardness and microstructure in electro discharge deposition of magnesium alloy

Abstract

In this study, an endeavour have been made to depositing the electrode materials over the surface of the magnesium alloy using electrical discharge machining (EDM) with WC-Cu powder compacted sintered electrode. Various process parameters such as compaction load, discharge current and pulse on time are selected to carry out the experiment in order to attain the maximum material migration rate (MMR) or deposition rate and microhardness (MH). It was concluded that the MMR and MH increased with increase in discharge current and pulse on time at low compacted electrode but it is decreased at lower discharge current and pulse on time. Highest MMR and MH were attained successfully at partial sintered low compaction load electrode. Microstructure evaluation has been carried out on deposited surface using scanning electron microscopy (SEM) and presence of electrode element in the deposited surface was confirmed by energy dispersive spectroscopy (EDS). Defects mechanism such as globules and craters are formed during EDC with high current and pulse on time respectively, which diminishes the surface roughness. It was observed that the compaction load is the influence parameter on the MMR and MH.

Keywords

• electrical discharge machining
• material migration rate
• scanning electron microscope