Tungsten Copper Contacts Cryogenic Treatment (2/2)

At present, cryogenic treatment mainly applied in tool steel, non-ferrous metal applications under development step, here we discuss that the tungsten copper contacts cryogenic treatment process conditions affect its properties. Tungsten copper contact is a psudoalloy, which is composed of two kinds of immiscible and has a great difference in physical and chemical properties metals. There is no phase change in the reaction and it is brittle so that it is difficult to adapt conventional heat treatment hardening process to improve its relative performance. Cryogenic treatment is undoubtedly an ideal choice.

Viewed from the micro-structure, after cryogenic treatment, W matrix disperse a large number of Cu phase and the organization has significantly refined, which is due to precipitation of Cu solute in W after cryogenic treatment. In addition, it also can be found that with the increase in the copper content, the segregation phenomenon is also becoming increasing apparently. Copper particles dispersed precipitated tissue thinning, and atomic displacement volume shrinkage, tungsten copper contact density and overall strength has also improved.

While its hardness and strength has greatly improved after cryogenic treatment, and electrical conductivity with increasing tungsten content decreases. This is due to cryogenic treatment makes a lot of precipitated Cu and W form a solid solution, and is proportional to the electrical conductivity of tungsten copper contacts with the copper content. Overall, tungsten copper contacts after cryogenic treatment, may be little alternative to tungsten copper copper-tungsten less, not only improves performance, but also reduce costs.

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