Titanium is "light and strong." We hear this often.
This statement isn't wrong, but it doesn't fully convey the true appeal of titanium as a material. That's because it's not lighter than aluminum, and not all types of titanium have the same strength.
Nevertheless, titanium is chosen for applications where performance is critical, such as in aircraft, medical devices, chemical equipment, motorsports, and vehicle components. The reason isn't simply "lightness" or "strength," but rather its overall capability, including the strength-to-weight ratio, corrosion resistance, and heat resistance.
In this article, we will clarify the differences between titanium, iron, aluminum, and magnesium through data and explain why NEXT SCIENCE uses 64 titanium in its products.
1. Titanium is lighter than steel, but heavier than aluminum
Density is fundamental when comparing the weight of materials. Comparing representative values, we get the following:
| Material | Density |
|---|---|
| Titanium | 4.54 g/cm³ |
| AISI321 Stainless Steel | 8.03 g/cm³ |
| 7075-T6 Aluminum Alloy | 2.80 g/cm³ |
| AZ31 Magnesium Alloy | 1.78 g/cm³ |
For the same volume, titanium is approximately 44% lighter than stainless steel. On the other hand, it is heavier than aluminum and magnesium.
In other words, the value of titanium is not that it is "the lightest metal." Its value lies in its ability to significantly reduce weight while maintaining strength comparable to steel materials.
2. "Specific strength" is key
When selecting materials, it's not just strength that matters, but also "how much weight is required to achieve that strength." This concept is known as specific strength.
For example, even a very strong material might not be suitable for parts requiring weight reduction if it's too heavy. Conversely, a light material cannot be used if it cannot withstand the necessary load.
Titanium alloys, particularly Ti-6Al-4V, often called 64 titanium, have a tensile strength of approximately 900 MPa under typical conditions. It possesses higher strength than pure titanium while having a lower density than steel materials. This "balance of strength and weight" is a major appeal of titanium alloys.
3. Pure titanium and 64 titanium are not the same
While both are called titanium, industrial pure titanium and titanium alloys have different properties.
Pure titanium excels in corrosion resistance and workability, used in chemical equipment, heat exchangers, and building materials. In contrast, 64 titanium is an alloy made by adding approximately 6% aluminum and 4% vanadium to titanium, officially known as Ti-6Al-4V.
64 titanium offers an excellent balance of lightness, strength, heat resistance, and corrosion resistance, and is widely used in aircraft components and high-performance machine parts. NEXT SCIENCE's titanium products also use this 64 titanium depending on the application.
4. Being strong is different from being resistant to deformation
Here, "strength" and "rigidity" are often confused.
Strength refers to resistance to breaking, while rigidity refers to resistance to deformation when a force is applied. Representative values for Young's modulus, which indicates rigidity, are approximately 200 GPa for steel, 110 GPa for titanium, and 70 GPa for aluminum.
Titanium is lighter and stronger than steel, but for the same shape, it is a material that flexes more elastically than steel. Therefore, rather than judging superiority solely by the material name, the design must consider the part's shape, dimensions, direction of load, and fastening conditions.
5. Resistant to heat and corrosion
Titanium forms a highly stable oxide film on its surface. This thin film protects the interior, providing excellent corrosion resistance in many environments, including seawater.
Another characteristic is its ability to maintain strength at higher temperatures than aluminum alloys. Beyond its lightness, it can maintain performance in environments where heat and corrosion are concerns, making it valuable in aircraft, chemical plants, and marine equipment.
6. The performance of a material and the performance of a finished part are not the same
Using high-performance materials does not automatically lead to high-performance parts.
Titanium is a material where machining conditions are difficult to control, and cutting heat tends to concentrate on the tool. All aspects—shape design, material selection, cutting, surface treatment, dimensional control, and fastening methods—affect the reliability of the finished product.
Bolts, in particular, are not merely components that are pulled. It is necessary to consider the clamping axial force, stress concentration in the threaded section, seating friction, repetitive loads, and combinations with mating materials. That's why design and machining that consider the application are crucial, not just the material's catalog values.
7. Why NEXT SCIENCE Uses 64 Titanium
NEXT SCIENCE uses 64 titanium not to present the material name as an added value, but as a means to achieve the necessary performance as a component.
Lighter than steel materials and possessing excellent specific strength and corrosion resistance, 64 titanium is suitable for lightweighting vehicle bolts and machine parts. However, considering cost and machinability, it's not ideal to make every part from titanium.
What's important is where, in what shape, and what material to use. At NEXT SCIENCE, we develop products that connect material properties to the value of the finished product, considering the application, load, and installation conditions.
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Continue reading here:
What is 64 Titanium (Ti-6Al-4V)? Differences from Pure Titanium and the Mechanism of its Strength
Reference: Tohoku University Institute for Materials Research, Mr. Naoya Masahashi, "Manufacturing Basics Lecture: Re-evaluating the Appeal of Metals - Part 1: Titanium," November 21, 2011
The physical properties and mechanical properties stated in this article are representative values from the reference material. The values may vary depending on material standards, composition, heat treatment, and processing conditions. This article describes material properties and does not guarantee the performance of individual products or vehicles they are installed on.