Aluminium, also known as aluminum in The United States of America, is a relatively light weight type of metal element which is favored for use in sports and racing vehicles, where extra weight reduces vehicle performance. It is usually used where titanium is too expensive of an option, which is typically on larger parts or parts that need to be machined rather than cast. Many modern vehicles are utilizing aluminium to reduce weight, improving fuel efficiency.
In addition to motorsport applications, aluminum is found in more and more production sports cars and family vehicles, not just for weight savings, but for crash safety benefits as well.
Electrical
Aluminum is a great conductor of electricity. It can be found in some sensors and may be the conductive material in some wires. However, copper is a better conductor and will typically be chosen over aluminum for important electrical circuits.
Heating & Cooling
Aluminum has great thermal transfer properties, and is the material of choice in many temperature transfer systems. It is commonly found in radiators, heater cores, condensers, AC lines, oil pans, and power steering coolers. Making all of these components out of aluminum also helps reduce the vehicle's weight and the cost of manufacturing, versus making them out of most other metals.