By choosing the correct combination of time, temperature and pressure, the controlled expansion (CE) alloys can be joined to each other, other Al alloys, other metals and ceramics by diffusion bonding.
Successful high-strength bonds have been made between all the CE alloys with and without use of an Al foil interlayer. However, individual combinations require qualification for specific applications requiring MIL STD testing.
Compound packages can also be produced. For example the package shown below produced by Pacific Aerospace & Electronics (PA&E) has a base of Osprey® CE7F alloy to match the required alumina carrier and sidewalls of Osprey® CE13F alloy to permit ease of machining the welding of aluminium feedthroughs and laser welding of a CE alloy lid.
In addition to joining several different CE alloys together one or more of the layers can be pre-machined to form closed channels (e.g. for water cooling) after bonding.
As an alternative to the above, the machined channels can be filled with high conductivity materials such as pyrolitic graphite, diamond composites (e.g. Diamond-SiC-Si) cooling fluids or phase-change materials. The enhanced conductivity areas or layers can be incorporated into the final part.