Titanium alloy is known for lightweight metal material, widely acclaimed across industries like aerospace, automotive, medical, sports, and beyond. Its special features, such as impressive tensile strength, resistance to corrosion, and stability in high temperatures, make titanium alloys a top choice for cutting-edge applications. Join us in this blog post as we delve into the distinctive properties of titanium alloys and how they find use in diverse industries.
What Is Titanium Alloy?
A titanium alloy is a type of metal made by combining titanium with other elements, like aluminum, vanadium, or iron. This combination enhances the properties of titanium, making it stronger, more resistant to corrosion, and suitable for various applications. Titanium alloys are known for their light weight, high strength, and durability, making them valuable in industries such as aerospace, medicine, sports, and manufacturing.
Titanium Alloy Properties
With the use of titanium alloy, widely employed in components like turbine blades and bio-materials due to its high specific strength and corrosion resistance. Despite these benefits, titanium has drawbacks like high friction and poor wear resistance. To address this, surface modification through nitriding is common but can reduce fatigue strength due to grain-coarsening.
The research aims to enhance the tribological properties of titanium alloy by developing a low-temperature nitriding process. The previous study successfully applied this to commercially pure titanium, maintaining fine grains. This study specifically looks at low-temperature nitriding of Ti-6Al-4V alloy, characterizing the surface layer formed, and assessing its impact on the alloy’s 4-point bending fatigue properties.
Titanium Mechanical Properties
Unalloyed, commercially pure titanium has a tensile strength ranging between 275 and 590 MPa. This strength is mainly influenced by the oxygen and iron content; higher levels of these elements result in increased strength. For commercially alloyed titanium grades, the tensile strength varies from as low as 600 MPa (e.g., Ti-3A1-2.5V) to as high as 1250 MPa (e.g., Ti-15Mo-5Zr-3AI).
Pure titanium remains stable up to around 300°C, owing to its specific strength and creep resistance. More complex titanium alloys maintain high strength even at temperatures up to approximately 500°C.
The fatigue strength (after 10^7 cycles) is approximately half of the tensile strength, and welding does not significantly decrease fatigue strength. In seawater, both commercially pure titanium and titanium alloys show almost no decline in fatigue strength.
The fracture toughness of titanium alloys ranges from 28 to 108 MPa m^1/2 and is inversely correlated with tensile yield strength. The specific fracture toughness depends on microstructure, with alloys having acicular structures exhibiting higher fracture toughness.
Chemical Properties Of Titanium
Titanium alloys are known for their exceptional chemical properties, notably corrosion resistance due to a protective oxide layer. This resistance extends to harsh environments, making them durable in aerospace, chemical processing, and healthcare. Their biocompatibility suits medical applications, while inertness ensures stability. Titanium alloys’ ability to withstand high temperatures widens their usage, from jet engines to industrial processes, making them versatile and reliable across diverse applications.
| Atomic number | 22 |
| Atomic mass | 47.90 g.mol -1 |
| Electronegativity according to Pauling | 1.5 |
| Density | 4.51 g.cm-3 at 20°C |
| Melting point | 1660 °C |
| Boiling point | 3287 °C |
| Vanderwaals radius | 0.147 nm |
| Ionic radius | 0.09 nm (+2) ; 0.068 nm (+4) |
| Isotopes | 8 |
| Electronic shell | [ Ar ] 3d1 4s2 |
| Energy of first ionisation | 658 kJ.mol -1 |
| Energy of second ionisation | 1310 kJ.mol -1 |
| Energy of third ionisation | 2652 kJ.mol -1 |
| Energy of fourth ionisation | 4175 kJ.mol -1 |
Physical Properties of Titanium Alloys
Strength and Durability
Titanium alloys stand out for their outstanding strength and durability, boasting the highest strength-to-weight ratio among metals. This quality makes them particularly well-suited for critical aerospace applications where both strength and weight are paramount. Additionally, these alloys excel in withstanding extreme temperatures, pressures, and challenging environments, earning them a prevalent role in aircraft engines, medical implants, and power generation systems.
Corrosion Resistance
Renowned for exceptional corrosion resistance, titanium alloys can bravely confront harsh environments like seawater, acids, and chlorides. The protective oxide layer on their surface enhances this resistance, positioning titanium alloys as ideal materials for marine, chemical, and oil and gas applications.
Biocompatibility
Another distinctive feature of titanium alloys is their biocompatibility. Resistant to corrosion in various bodily fluids and low in toxicity, titanium proves suitable for medical implants. Dental implants, artificial hips and knees, cardiac pacemakers, and bone fixation devices are commonly crafted from titanium alloys, ensuring they can reside in the human body without triggering adverse reactions.
Machinability
Despite their formidable strength and durability, titanium alloys exhibit relative ease of machinability. Unlike metals like steel and aluminum, titanium alloys do not work harden during machining. This characteristic empowers manufacturers to produce intricate parts with tight tolerances and minimal scrap rates, making titanium alloys an excellent choice for the aerospace and medical industries.
Lightweight
Highlighting a previous point, titanium alloys are lightweight, presenting another significant advantage. Integration of these alloys in aerospace applications results in reduced aircraft weight, leading to lower fuel consumption and emission rates. The lighter weight of titanium implants also lessens mechanical stress on a patient’s bones.
Conclusion
In summary, titanium alloys boast unparalleled properties that render them unique and highly coveted across diverse industrial applications. From aerospace and automotive to medical implants and sports equipment, these alloys offer an exceptional combination of strength, durability, corrosion resistance, biocompatibility, and lightweight. With ongoing technological advancements and innovations, we anticipate witnessing even more exciting applications for titanium alloys in the future.
