Commercial manufacturers have used titanium since 1947 when just two tons of the versatile metal were produced each year. Making use of titanium’s superior strength-to-weight ratio along with its robust anticorrosive properties, governmental and military interests drove titanium production to 2,000,000 pounds annually by 1953. Today, the aerospace industry accounts for 73% of titanium used in the U.S., but military manufacturers are also increasingly adopting titanium for their own advanced hardware applications. Military and aerospace manufacturers set high-performance standards for their products, which face extreme conditions and must employ exceptional strength and durability. The challenges these applications face in their operational lifetimes require a wide range of high-quality metals and alloys, including:
Stainless steel: This metal resists corrosion in humid conditions and forms crucial parts of mess kits, firearm gas tubes, dog tags, and other items. Stainless steel comes in a variety of grades, including magnetic and nonmagnetic types.
Carbon steel: This steel lacks minimum content specifications for the desired alloying effect with nickel, chromium, molybdenum, cobalt, and all other elements. Although carbon steel rusts if left unattended, its versatility and exceptional strength achieved with heat treatment enable it to appear in applications throughout the military and aerospace sectors, particularly in bayonets and knives.
Nickel alloys: These alloys offer low electrical resistance and magnetism, minimal thermal expansion, and reduced memory or hysteresis. These attributes make nickel alloys essential parts of aircraft turbine engines and nuclear power systems in submarines and aircraft carriers.
Titanium: Successfully using titanium resolves a host of engineering problems. Titanium offers the same strength as steel but at half the weight, and it weighs the same as aluminum while being twice as strong. Additionally, titanium offers one of the highest strength-to-weight ratios of all metals. Its exceptional performance at high temperatures as well as its superior corrosion resistance renders it an important component for a number of applications.
Additionally, its versatile machinability enables the fabrication of titanium protective armor pieces as well as reliable structural elements. Titanium also exhibits excellent galvanic, thermal expansion, and conductive compatibility characteristics, opening the door for more titanium applications in conjunction with the increased use of carbon composites for military and aerospace hardware.
Titanium Applications in the Military
Titanium’s exceptional lightweight strength and superior anticorrosive properties make it a valuable resource to every branch of the military. The US Navy uses titanium for shipboard components that come into direct contact with the ocean, including propeller shafts, underwater manipulators, and rigging in the surface fleet. It also forms an essential component of submarine ball valves, cooling and piping systems, heat exchangers, and exhaust stack liners.
The Air Force takes advantage of titanium’s efficient strength-to-weight ratio, using it in landing gear, airplane frames, brackets, and wing access panels. Titanium also lines armored personnel carriers used in the Army and Marine Corps, and researchers are currently testing its feasibility for tank armor and personal protective equipment.
Titanium in the Military and Aerospace Industries
Titanium’s easy machinability characteristics and versatile alloying properties make it easy to combine in high-quality alloys with aluminum, vanadium, and other elements. Titanium alloys appear in aircraft, ships, missiles, and spacecraft in high-performance parts including firewalls, helicopter exhaust ducts, and critical structural parts.
The material’s surface has a chemically inert oxide, resulting in better resistance to corrosive mineral acids and chlorides. In challenging military and aerospace environments, titanium’s tensile and fatigue strength also help it resist fatigue and fractures. Its tensile strength of 20,000–200,000 psi and heat resistance to temperatures above 1,112°F (600°C) enable it to perform well in any environment.
Titanium’s versatile alloying properties ensure that demand for the metal in military and aerospace applications will only increase, especially as composite construction becomes more dominant in high-performance military aircraft such as the F-22 Raptor. The Raptor’s performance capabilities depend on the extensive use of titanium and its composites. Titanium contributes 42% of all structural materials by weight to the state-of-the-art aircraft. In contrast, steel and aluminum comprise just 6% and 16% of the F-22’s airframe, respectively.
A Bright Outlook for Titanium
In the past, using materials like aluminum and steel compromised performance in applications including engine and turbine components along with structural capacity in harsh corrosive environments. Titanium’s compatibility with other metals in alloys as well as composite materials such as carbon fiber and fiberglass will continue fueling strong demand for this material in the military and aerospace industries as well as the commercial sector in general.