Aluminium graphite in power electronics - proven to be more durable than standard materials such as copper or aluminium

The problem—thermomechanical stresses destroy joints 

In power electronics, semiconductor chips, substrates, and housings are connected to one another via solder or bonding joints. Every temperature change during operation generates mechanical stresses because the different materials expand at different rates. Copper base plates with a coefficient of thermal expansion of 17 × 10⁻⁶/K expand considerably more than ceramic substrates or semiconductor materials. The result is thermal fatigue—stresses that build up with each load cycle and ultimately lead to delamination of the solder joint. 
This is not a theoretical risk. In a comparative study of thermal shock behavior (-40 °C to +125 °C), copper base plates showed significant delamination damage after just 1,000 cycles. Aluminium-Graphite base plates from Schunk Carbon Technology showed no damage whatsoever even after 2,000 cycles. 

The solution—Aluminium graphite with a matched CTE

Aluminium graphite (ALG) is a metal matrix composite whose coefficient of thermal expansion is precisely matched to the surrounding semiconductor materials and substrates. It combines high thermal conductivity with low density—two properties that copper and other conventional heat sink materials do not offer in this combination. 
The key advantage over copper: Aluminium Graphite transfers heat faster and distributes it more evenly—while weighing significantly less and having a CTE that matches the adjacent materials rather than working against them.