Definition of Titanium Hardness
A good indicator of the nature of a metal is its hardness, which in layman’s terms means whether or not the metal material will deform or leave scratches when subjected to external forces. Do you know what titanium hardness specifically refers to? The hardness of titanium refers more to the hardness of titanium alloys, different hardness of titanium alloys will show different states and applications will also change, this article will take you into an in-depth understanding of titanium hardness.
Titanium Hardness Classification
Common classifications of titanium hardness are these:
Pure Titanium, this material has a 99% content of the element titanium. Also because of its high purity, it has a lower hardness. Its hardness ranges from 120-180 HV (where HV is the Vickers unit of hardness). Pure titanium is classified as grade 1-4.
Since titanium is very compatible with living organisms, this low to medium-hardness grade of pure titanium can be used in artificial joints, dental implants, and surgical instruments.
Alpha-beta Type Titanium Alloy, this kind of name you may not quite understand, I’ll give you a more specific category, 6Al-2Sn-4Zr-6Mo titanium (commonly known as titanium 6240), it belongs to the medium hardness of titanium alloy, with a hardness range of 300-380HV, hardness level is 5.
It is often used in aircraft structural components, engine parts, and flight control systems due to its strong wear resistance and hardness to meet various large instrument manufacturing standards.
Beta Titanium Alloys like Ti-38644, Ti-15-3, and Ti-15-3-3-3 are some of the more common ones. It has a hardness rating of 23 and a hardness range of 350 to 450 HV.
These medium to high-hardness titanium alloys are more common in areas such as the manufacture of high-performance automotive components, where their use improves the corrosion resistance of automotive components.
Alpha Titanium Alloys, which have a hardness rating between 200 and 350 HV, are of low to medium hardness.
This type of alloy is used more often to make chemical equipment and its storage containers.
High-strength Titanium Alloys, Ti 6al 4v, are the most typical type of high-strength titanium alloy, with hardnesses ranging from 400 to 500 HV.
These alloys are widely used in the manufacture of seawater contact equipment and components, such as desalination equipment and large ship components.
Here are some details about these types. This may bring you a more intuitive reading experience.
| Name | Titanium Content | Other Elements | Features |
| Pure Titanium | >99.5% | Non-magnetic and Biocompatible | |
| Alpha-beta Titanium Alloy | 85%-95% | Aluminium, Vanadium, Tungsten, Manganese, etc. | Strong Toughness, Corrosion Resistance, High Temperature Resistance, High Workability |
| Beta Titanium Alloy | >90% | Niobium, Tungsten, Zirconium, Nickel, etc | High Strength and Plasticity |
| Alpha Titanium Alloy | >90% | Aluminium, Vanadium, Manganese, Iron, etc | Corrosion Resistance and Weldability |
| High Strength Titanium alloy | >90% | Aluminium, Vanadium, etc | High strength and Low Weight, High Temperature and Corrosion Resistant |
Test Methods for Titanium Hardness
Vickers Hardness Test: In short, the titanium material is indented by a diamond, and the hardness value is calculated by measuring the diagonal length of the indentation.
Brinell Hardness Test: Generally it means indenting the surface of the titanium alloy with a 10mm tungsten steel ball tip and calculating the hardness by the diameter of the indentation.
Rockwell Hardness Test: An indenter of different sizes and shapes is used to apply pressure to both ends of the material and the results are obtained by measuring the depth of deformation.
Factors Affecting the Hardness of Titanium
Composition: Changing the hardness of a metallic material can be achieved by adding some other metallic elements. The addition of aluminum, vanadium, and other additives during the hardening process can increase the hardness of titanium.
Heat Treatment Process: Different heat treatment processes such as tempering and quenching also affect the hardness of titanium.
Impurity Content: Impurities here refer to the content of elements such as oxygen, nitrogen, carbon, etc. Generally speaking, the higher their content, the higher the hardness of the titanium alloy.
Crystalline Grain Size: Titanium with fine crystalline organization is harder than coarse crystals
Degree of Plasticity: Proper cold or hot working can increase the hardness of a titanium alloy, but overdoing it can be counterproductive and make it more brittle.
Conclusion
The above is a more comprehensive description of titanium hardness, I hope this article can help you choose the titanium material you need. if you have other questions, please feel free to ask!
