Audi A8 body is made from 铝合金

铝合金 has many kinds. 合金 这两字太有讲究。Can be cheap, and soft. also can be really strong.

All Apple notebook, Mac Air and Mac Pro are very soft 铝合金too. It's very easy to get scratches and dents. Apple fans just tolerant this. However, this is not case for phones because phones often are used outdoor, and people take less careful than notebooks.