Aluminum Alloys and Aluminum Solution Treating The aluminum metals in cars are usually alloys, which means the aluminum contains another substance. Aluminum alloys typically contain copper, magnesium, manganese, silicon, tin or zinc. The addition of these other materials causes specific effects in aluminum’s strength, flexibility, or other properties to make them strong enough for low-stress areas such as the cab’s floor, cowl, and inner door panels. Treatment of the aluminum alloys also influences the physical properties of the sample. Heat-treating aluminum after the forming process helps increase the strength of the aluminum. Aluminum solution treating and aging is therefore an