Titanium alloys are an important class of materials to be used in engineering and applied science. Titanium alloys are generally characterized by strong interatomic bonds, good specific strength and plasticity, high corrosion resistance, and relatively low cost. These characteristics are responsible for the frequently increasing use of these alloys in numerous engineering applications.
One of the most frequently used titanium alloys is Ti-6Al-4V. It is a two-phase α + β titanium alloy that is widely known for its light weight and high strength to weight ratio. This Ti-6Al-4V alloy combines a strong α phase with a ductile β phase, providing a good compromise among mechanical properties, toughness, and weldability. Ti-6Al-4V alloy exhibits very high strength (up to 1300 MPa), excellent hot-workability, and good resistance to stress-corrosion cracking. Additionally, it is relatively inexpensive, making it the most commonly used titanium alloy in the aerospace, automotive, biomedical, and chemical industries.
Other titanium alloys that have been studied extensively include Ti-15V-3Al-3Sn (Ti-15-3) and Ti-15Mo (Ti-15-1). Both of these alloys are two-phase α + β titanium alloys that are known for their excellent mechanical properties, including strength and creep resistance. Ti-15-3, in particular, has a higher tensile strength than Ti-6Al-4V, a higher hardness, and better overall corrosion resistance. Ti-15Mo, on the other hand, has superior creep resistance. It is often used in applications that require elevated temperatures and the resistance to creep stress, such as aircraft engines.
It should also be noted that many titanium alloys possess good thermal properties. In particular, titanium alloys with a higher aluminum content tend to have better thermal properties, with less thermal expansion, improved creep resistance, and higher oxidation and melting temperatures. This makes Ti-6Al-4V and Ti-15-3 popular choices for use in high temperature applications.
In summary, titanium alloys have a wide range of applications due to their excellent mechanical, thermal and corrosion properties. Ti-6Al-4V is the most commonly used titanium alloy, due to its good strength, weldability and low cost. Ti-15-3 provides higher strength and corrosion resistance than Ti-6Al-4V, and Ti-15Mo offers superior creep resistance. Additionally, titanium alloys with higher aluminum content tend to have better thermal properties and are more suitable for elevated temperature applications. For these reasons, titanium alloys are increasingly being used in numerous engineering applications.
