Milling performance of Ti2AlNb by DC short electric arc machining based on different electrode materials

Abstract

In this paper, a novel e cient and sustainable electrical discharge machining method, referred to as short electric arc machining (SEAM), is proposed to solve the problems of low e ciency, severe tool wear, and high cost of Ti2AlNb machining by traditional methods. The mechanism of SEAM with different voltages and tool electrode materials (W70Cu30, high-purity graphite, copper-plated graphite, and 304 stainless steel) is studied using a DC power supply, and the workpiece material removal rate (MRR), surface roughness (Sa), and relative tool wear rate (RTWR) are analyzed. In addition, the surface morphology, cross-sectional morphology, elemental distribution, and microhardness of Ti2AlNb after processing are investigated. The experimental results show that under 28 V, the W70Cu30 electrode achieves the highest MRR of 2571 mm 3 /min, which is higher than that of the other three electrode materials. It has also the lowest RTWR of the electrode and a relative electrode loss of only 0.0974%. The lowest surface roughness and heat affected layer of the workpiece after machining are 53.2 µm and 56.54 µm, respectively. The absolute difference of the width of the cross-section of the workpiece is the smallest, and the hardness of the recast layer of the workpiece is close to the hardness of the base metal, which is conducive to further processing. the thickness of the workpiece heat affected layer after machining with copper-plated graphite and 304 stainless steel electrodes is 64.6 µm and 72.4 µm, respectively.(5) The EDS analysis shows that after SEAM, a large amount of carbon, oxygen, and metal elements adheres to the workpiece surface, which indicates that after carburization and oxidation of the workpiece material, the tool electrode material and the conductive medium occur. The surface hardness of the workpiece machined by both high-purity graphite and copper-plated graphite electrodes signi cantly increases. Finally, the hardness values gradually decrease with the increase of the surface depth.

Research on the ultrasonic vibration-assisted short electric arc milling process of Inconel 718

“…The essence of ultrasonic short electric arc composite processing is to superimpose an ultrasonic vibration system on the tool electrode or workpiece based on ordinary short electric arc discharge processing to improve the discharge processing conditions. In the familiar short electric arc discharge process, mainly shown in Figure 1a, as the distance between the electrode and the workpiece decreases, the workpiece and the electrode surface form a discharge channel and produce a high-energy arc so that the discharge region has a large number of Joule heat, the processing of the workpiece is made by the high temperature of the charged particles melted and vaporized to achieve the purpose of the etching of the material [27].…”