Applications of Titanium and its Alloys
Today half of all titanium alloys manufactured end up in aerospace applications. Aerospace was the first industry to gain from titanium’s outstanding strength to weight ratio. In the 1950s, the Soviet Union pioneered the manufacture of titanium. The strategic importance of the metal during the cold war meant surplus titanium sponge was held by the US Defence National Stockpile and efforts were made to encourage the growth of the industry in the US.
Over the last 60 years, jet engines have experienced enormous improvements in thrust to weight ratio and efficiency as a direct consequence of Titanium. General Electric calculates that titanium usage has improved thrust to weight ratios by 350% and engine efficiency by 45%. The management of microstructure and quality has also seen a 90% improvement in safety.
The first aircraft to use titanium in the bulk of its construction was the US air force’s SR 71 blackbird. 85% of the aircraft’s structure was comprised of Ti. Prior to the SR71 the exorbitant cost of the metal meant it was used only sparingly.
The commercial aviation sector saw widespread use of titanium in the 1960s. Concorde would not have been possible without it. In aviation weight savings, spatial limitations and operational temperature are all factors in the choice of titanium alloy.
The Boeing 777, 787 and the Airbus A380 all use near beta titanium alloy in their landing gear. The A380 and 777 use Ti-10V-2Fe- 3Al (Ti 10-2-3) which offers weight savings over the traditional grade 5 Ti 6Al 4V; whilst the Boeing 787 uses Ti-5Al- 5V-5Mo-3Cr (Ti-5553) which has improved strength and hardness.
Jet Engines make use of Ti-6Al-4V titanium alloy which is used to make turbine compressor blades but it is not used in areas with a temperature greater than 400 degrees due to the risk of combustion.
Titanium is used in also tanks and other vehicle and personal armour. Despite its high cost the safety payoffs are considerable. The USAF A-10 Thunderbolt II features a titanium bathtub enclosure to protect the pilots.
Titanium is the metal of choice for offshore oil rigs where its corrosion resistance makes the metal ideal for prolonged
exposure to salt water and corrosive substances. Titanium is also used for the cathodic protection of steel in marine environments and underground structures like offshore wind turbines, where it can provide protection for the lifespan of the installation.
Currently, corrosion is one of the chief problems facing the operational life span of naval and merchant vessels; titanium can mitigates these issues, titanium propellers are becoming increasingly common, whilst the office of naval research is exploring the future of titanium hulled vessels.
Titanium is the number one metal for use in biomedical applications where the need to have an inert, strong biocompatible metal is critical. Titanium is vastly superior to the organic material that it replaces; material that may be unsuited for critical applications in the aerospace industry may serve as dental implants, replacement hips and other orthopaedic implants.
Titanium’s ability to osseointegrate is phenomenal meaning that it can fuse with bone. This property was first discovered in the 1940s and has played a significant role in the development of joint and bone replacement, and improvements in external prosthetics; where a titanium rod protrudes from the skin and is used to attach prosthetics to the bone.
Chemical plants make widespread use of titanium. The metals inert ceramic layer makes it ideal for highly corrosive chemical plants where it is used in pumps, valves and heat exchangers. Traditionally it has been confined to oxidising environments. When alloyed with palladium it can be used in reducing environments like acids and chlorides the main alloys used in these circumstances are grade 11 and grade 17.
Nuclear waste storage requires corrosion resistant containers capable of lasting hundreds of thousands of years. Titanium is one of the few metals up to the task.
Titanium is used in a growing range of consumer applications. Its inert nature makes it ideal for jewellery as it does not react with the skin and cause allergies like copper and nickel based accessories. This makes it a popular alternative for wedding rings bracelets and cuff links. The advent of 3D printing, whilst inadequate for controlling titanium microstructure for aerospace applications, is perfect for creating bespoke designs for consumers.
Titanium is used in everything from designer sunglasses, high-end toothbrushes, sporks, watches, performance car exhausts, bikes, golf clubs and computer cases.
Titanium is seeing increased adoption in architecture. Its properties make it very effective in these applications. It has similar rates of thermal expansion to glass and concrete. That means it, can be used effectively with these materials without suffering from thermal stress. Its corrosion resistance also gives it a low lifetime cost.