Unlike tool steels, the surface structure resulting from electrical discharge machining (EDM) of copper beryllium alloys is soft and not susceptible to cracking. In the high strength copper beryllium, the surface layer consists of a resolidified zone and a heat-affected zone. The hardness of the heat-affected zone typically ranged from that in fully annealed to highly overaged condition. The depth of the surface layer affected by EDM increased with the electric discharge current and pulse duration. The thickness of the zone nominally ranged from 5 to 15 μm for the high strength copper beryllium alloys, compared to 2 to 200 μm reported for tool steels in the literature. No significant changes in hardness or surface microstructure were observed in the high conductivity copper beryllium, compared to the base metal. Thus, no deleterious effects of EDM were detected in the copper beryllium alloys.
|Original language||English (US)|
|Number of pages||11|
|Publication status||Published - Dec 1 1998|
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