What materials are used to make the Audi R8's frame?

I've heard that the Audi R8's frame is made from a blend of different materials, what are these materials and why were they chosen?

Audi has designed their R8 with an advanced frame made primarily from carbon fiber and aluminum, allowing for maximum strength and agility while maintaining a lightweight structure.

The frame of the Audi R8 is made from a combination of carbon fiber and high-strength steel, providing both durability and torsional rigidity for improved handling and overall performance.