What materials are used to make the Audi e-Tron body and why?

I am wondering what materials are used to make Audi e-Tron bodies and why those specific materials were chosen. I am interested in the structural integrity, sustainability, and weight of the body materials.

The body of the Audi e-Tron is made primarily of aluminum, with some high-strength steel and carbon fiber components. This combination of materials allows for a lightweight yet strong and rigid body, resulting in improved handling and driving efficiency. Aluminium was chosen for its low weight and high strength, while the use of steel adds extra structural rigidity. Carbon fiber components further reduce weight and increase energy efficiency.