Stronger than some steels, but nearly 45% lighter…twice as strong as aluminum, but about 60% heavier…that’s titanium for you! Titanium is a shiny, silvery metal that is very strong, yet very light. It features very high corrosion resistance (even in seawater and chlorine) and the highest strength relative to its density of any other metal.
Did you know? Titanium was first discovered in England in 1791 and was named after the Titans of Greek mythology.
Titanium is often combined with iron, aluminum, molybdenum, and vanadium to form alloys. These alloys are strong and tough, lightweight, corrosion-resistant, and can withstand extremely high temperatures. The most commonly used titanium alloy is Ti-6Al-4V. Some call it the Cadillac of the titanium industry, others call it the workhorse alloy!
Introduction to Ti-6Al-4V Titanium Alloy
Ti-6Al-4V, also known as Grade 5 Titanium Alloy, consists of 6% aluminum (Al), 4% vanadium (V), about 0.25% iron, and 0.2% oxygen, with the remainder being titanium (Ti). It is an alpha-beta alloy, as aluminum is the alpha stabilizer and vanadium is the beta stabilizer, and its properties can be adjusted by heat treatment.
- Characteristics of Ti-6Al-4V
High corrosion resistance: Due to the spontaneous formation of a continuous and consistent oxide layer when exposed to oxygen, Ti-6Al-4V has extremely high corrosion resistance and can resist corrosion from seawater and chlorine. This makes it ideal for underwater and marine applications such as submarines, offshore oil and gas equipment, and the chemical industry.
High strength and low density: The high strength and low density of Ti-6Al-4V give it important applications in the military, aerospace, and automotive industries. It is used in aircraft structural components, hydraulic systems, engine components, helicopter rotor blades, rockets, and spacecraft, among others. Its high strength-to-weight ratio is also very useful in racing cars and is often used in components such as gearboxes.
Heat Treasurement, Weldability, and Machinability: It can withstand extremely high temperatures (up to 750°F) and is easily welded and machined, which makes it attractive for applications such as various engine components and gearboxes in the automotive industry.
Excellent Biocompatibility: The biocompatibility of it makes it an ideal material for the medical field. It does not react with body fluids, surrounding tissues, or bones, and aids in osseointegration. The porous structure made from this alloy allows for vascularization and tissue adhesion to implants, which speeds up recovery for patients undergoing hip and knee replacement surgeries. The alloy is also used in prosthetics, bone plates, and rods, among others.
Non-Magnetic: It is non-magnetic, which means that people with this implant in their bodies can safely undergo scans such as X-rays, MRIs, etc. Ti-6Al-4V is also used in medical devices and surgical instruments such as needles, forceps, pliers, scissors, drills, etc.
- Disadvantages of Ti-6Al-4V
Poor shear strength: It has poor shear strength and surface wear resistance, so it tends to slip or bite when in contact with sliding parts. To overcome this problem, oxidation and nitriding treatments are often used.
Corrosion to strong acids: Despite good general corrosion resistance, Ti-6Al-4V alloy is not suitable for use in strong acid environments (such as hydrochloric acid or sulfuric acid) because it will destroy the protective oxide layer on the alloy.
Summary
Ti-6Al-4V is an amazing material that has applications in many industries. As technology advances and new uses for its properties are discovered, its use in our daily lives will continue to grow.
