Study of the recast layer of a surface machined by sinking electrical discharge machining using water-in-oil emulsion as dielectric

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• 作者：Yanzhen Zhang^a ; Yonghong Liu ; ^a ; ^{liuyh@upc.edu.cn} ; ^{liuyhupc@126.com} ; ^{liuyhcup@163.com} ; Renjie Ji^a ; Baoping Cai^a
• 关键词：Electrical discharge machining (EDM) ; Recast layer ; Water-in-oil ; Emulsion
• 刊名：Applied Surface Science
• 出版年：2011
• 出版时间：1 May 2011
• 年：2011
• 卷：257
• 期：14
• 页码：5989-5997
• 全文大小：2133 K

文摘

Electrical discharge machining (EDM) caused a recast layer to form at the machined surface of the workpiece. The characteristics of the recast layer have a great relationship with the type of dielectric. The research work in this paper aims to acquire a profound knowledge of the recast layers of a surface machined by sinking EDM using water-in-oil (W/O) emulsion as dielectric. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrograph (EDS) and micro hardness analysis were performed. The characteristics of the recast layer formed in W/O emulsion were investigated by comparing them with those of the recast layer formed in kerosene and de-ionized water dielectric. It was found that the recast layer formed in W/O emulsion exhibited larger surface roughness, thickness and micro hardness compared with that formed in kerosene and de-ionized water. Both carbide and oxide were detected in the recast layer formed in W/O emulsion whereas only carbide was detected in the recast layer formed in kerosene. Due to the higher supersaturation of gases in the melted material, the recast layer formed in W/O emulsion was found to possess more micro-voids than that formed in kerosene and de-ionized water.