Surface Modification Process using TiH2 Green Compact Electrode by Electrical Discharge Machining

Abstract

A surface modification technology with electrical discharge machining has been applied to cutting tools, molds and dies. A Ti-based powder composite structure electrode is used in this method, a highspeed modification technology which can generate a thin and hard layer on a substrate. In this report, experiments using a Tile green compact electrode are described. The results of the experiments are as follows 1) The piled layer is functionally graded in atomic content and hardness which reaches 3000HV at the top of a 10-m-thick layer in spite of voids involved. 2) The thickness and hardness are uniquely determined by the supplied energy density. The wear length of the electrode is reduced according to the decrease of its area due to the bubbles in the gap region. 3) The layer grows rapidly at the beginning of machining and then its hardness increases. After the maximum piling rate, the hardness decreases owing to the change of thermal properties of the piled layer.