Tungsten Copper Alloy: Properties, Grades, and Heat-Sink Applications

Tungsten copper (WCu) is a composite of two metals that do not alloy: a tungsten skeleton infiltrated with copper. The result inherits tungsten density, low thermal expansion, and high temperature strength, together with copper conductivity and arc resistance.

By shifting the tungsten-copper ratio, the properties move predictably between conductivity and expansion control — which is why WCu is specified wherever heat must move but dimensions must stay stable.

Grades are named by weight ratio. W90Cu10 minimizes thermal expansion for the most expansion-critical packaging; W70Cu30 maximizes conductivity within the family. Common engineering grades include:

In electronic packaging, WCu bases and lids carry heat out of RF devices and power modules while matching the expansion of ceramic and semiconductor neighbors. In electrical contacts, the alloy resists arc erosion under repeated switching. In EDM, tungsten copper electrodes hold detail where copper alone erodes too quickly.

Machinability is workable but different from pure copper: carbide tooling, controlled feeds, and realistic tolerance expectations should be part of the drawing review.

The fastest route to an accurate quotation is to fix the grade ratio, form, and finish together:

Choose the grade ratio by deciding whether expansion matching or conductivity dominates the application, then specify density and geometry. WCu rewards buyers who define the joining and finishing route early.