Aircraft construction utilizes a multitude of different metals. Many of the metals are chosen because they possess the most desirable characteristics for aircraft structures and parts. These qualities are extreme strength, low weight and corrosion resistance, and the ability to withstand high temperatures. Aircraft wings are only one of the structural components that utilize titanium.
Titanium was discovered in 1791. It is one of the most abundant metallic elements on earth, but it wasn’t used commercially until the 1950s. Titanium is used for several purposes, including automotive, surgical and industrial applications. But it may be most well known as an important material used in constructing modern aircraft.
During flight, aircraft wings provide the lift and the rest of the aircraft, basically, hangs from the flying wings. This produces incredible stress on the wing roots, where the fuselage connects to the wings of an aircraft. This high stress area requires a very strong metal like titanium, which is as strong as some types of steel. Many wing attachment bolts are also made from titanium.
Weight is the natural enemy of flight. Aircraft wings need to have fantastic strength, but that strength is usually accompanied by greater weight. Titanium has an excellent strength-to-weight-ratio. It is as strong as steel, but only half the weight. Though it is heavier than aluminum, it significantly stronger.
The stresses and speeds of flight can cause high temperatures. A metal like titanium, with its ability to withstand very high temperatures, is perfectly suited for this type of heat. Some aircraft wings encounter even more severe heat extremes, especially on aircraft that travel faster than the speed of sound. Titanium is especially well-suited for the heat generated from the tremendous friction of supersonic flight.
Corrosion is one of the biggest dangers to aircraft structures. Aircraft metals are treated to enhance corrosion resistance. Corroded airframes and aircraft skins can cause catastrophic failures in the metals. Titanium’s resistance to corrosion is a result of a naturally occurring oxide film that forms on titanium when it contacts air. This corrosion resistance is important in many applications other than aircraft structures.