Titanium is a chemical element with the symbol Ti and atomic number 22. It is a lustrous transition metal with a silver color, low density, and high strength, and it resists corrosion in seawater, aqua regia, and chlorine.
Titanium has the lowest density of all metallic elements. Titanium is as strong as some steel but is only one-third the weight. Titanium’s strength-to-weight ratio makes it useful for many applications. Titanium alloys are 50% heavier than steel but 7-10 times stronger.
Why use titanium?
Titanium metal is resistant to corrosion. It is used in medical applications such as implants and prosthetics. Titanium alloys have the strength to withstand extreme environments and can be cast into complex shapes, such as tubes, bars, plates, and rings. The bodies can be machined to create components that have complex geometries.
Some titanium alloys have high specific strengths. Ti-6Al-4V has a particular strength of about 1.7 times that of aluminum alloy 6061-T6, which is one of the reasons why titanium alloys are valued in aerospace applications. They are used where high temperatures or cyclic loads are applied to parts—for example, used in aircraft engines.
Despite its premium price tag, titanium is a trendy material. Reasons to use titanium include:
- High strength
- Corrosion resistance
- Good strength-to-weight ratio
- Good machinability
- Surface treatment options
What are the disadvantages of titanium?
Titanium has high corrosion resistance; however, titanium metal is more robust than steel and lighter than aluminum, making it a better choice for applications that require strength and weight. Titanium metal has some disadvantages. It is expensive and difficult to machine and cannot be welded.
Also, Titanium has lower strength than steel (but higher than aluminum) and is more expensive. Titanium cannot be hardened by heat treatment, but it can be hardened by cold working. Titanium alloys work to set rapidly, so machining should be conducted at high speed and minimum positive feeds.
Common titanium grades
The Most Popular Materials
I choose some popular and most used materials in the mass production.
Titanium Gr5 Ti-6Al-4V TC4
Titanium Grade 5 or Ti 6Al-4V is the most popular alloy of titanium. Its primary alloying elements are aluminum and vanadium. It also contains a small amount of nickel, palladium, and ruthenium that improve its corrosion resistance far above standard titanium. This alloy is significantly stronger than Grade 2 and retains its corrosion-resistant properties at a wide temperature range. Grade 5 is a common choice for engine components and aircraft airframes.
Titanium Grade 2
Stronger than Grade 1, This grade is essentially a pure (99%) form of unalloyed titanium. It has excellent corrosion resistance characteristics and is easier to machine than other titanium alloys. Grade 2 is typically the best option when aqueous corrosion resistance is desired. Desalination components and medical implants are some of their applications.
Titanium Grade 1
Pure Titanium Grade 1 is the softest titanium and has the highest flexibility. It has an excellent cold forming characteristic and provides superior corrosion resistance. It also has excellent welding properties and high-impact toughness.
What colors does titanium come in?
Surface finishes include:
- Bead blasting
Titanium can come in a wide variety of colors, but the most common ones are gold, silver, blue, purple, green, red, yellow, and grey. It also goes through different color changes. As Titanium gets older and more exposed to oxygen, it will turn a patina color.