Introduction

Titanium Grade 2 and Grade 5 are two commonly used titanium powder materials. They differ in composition, properties, and applications. This article aims to highlight the differences between them and clarify the various types of titanium materials.

Fig 1. Ti-6Al-4V Powder

Classification and Grades of Titanium Powders

Before distinguishing Titanium Grade 2 and Grade 5, let’s explore the world of titanium powders and see how they are classified.

Titanium and Titanium Alloy Powders Are Classified Based On:

• Composition
• Microstructure: α-phase, β-phase, and α+β-phase
• Physical Properties
• Application Fields

1. Commercially Pure Titanium Powders

These titanium-based powders contain mainly titanium (Ti) with little impurities like oxygen, nitrogen, carbon, hydrogen, and iron. These can be classified further based on their impurity contents, notably oxygen and other impurities:

• Grade 1: This is the lowest in terms of oxygen content ≤ 0.18%, with the highest ductility, the lowest strength, best formability, and weldability. Grade 1 finds application majorly in high corrosion resistance and weldability applications: chemical equipment, ships, and implants used in medical service.
• Grade 2: This has a maximum oxygen content of ≤ 0.25% and is considered to have good all-round performance. Grade 2 is the most commonly used grade of pure titanium; this is typically found in pipelines, heat exchangers, and pressure vessels.
• Grade 3: This has a higher oxygen content, ≤ 0.35%, therefore it gives higher strength along with slightly lower ductility, which makes it suitable for use where higher strength is required.
• Grade 4: This grade has the maximum oxygen content of ≤ 0.40% and offers the best strength associated with good corrosion resistance; it will build most chemical, marine, and medical equipment.

2. α-type Titanium Alloy Powders

These powders primarily consist of the α-phase, which gives excellent oxidation resistance and high-temperature performance.

• Ti-5Al-2.5Sn: This is a typical α-alloy powder containing 5% aluminum and 2.5% tin. Mainly, It’s used for its good high-temperature strength and corrosion resistance in aerospace engines and high-temperature structural parts.
• Ti-8Al-1Mo-1V: This contains 8% aluminum, 1% molybdenum, and 1% vanadium, which gives it high tensile strength and creates resistance. It is applied in normally used aerospace engines and hot-end parts.
• Ti-6Al-2Sn-4Zr-6Mo: This alloy powder, containing 6% aluminum, 2% tin, 4% zirconium, and 6% molybdenum, has excellent high-temperature strength and creep resistance, often used in aerospace engines and hot-end components.
• IMI 685: A titanium alloy containing aluminum, tin, zirconium, and molybdenum; it has a high high-temperature strength for application in high-temperature structural parts.

3. β-type Titanium Alloy Powders

These are powders mostly of β-phase. In order to form these alloys, a large quantity of β-stabilizing elements is added. It includes molybdenum, vanadium, chromium, and iron. All these features offer good forgeability and high strength.

• Ti-10V-2Fe-3Al: This metal has very high strength with great forgeability and is mainly utilized in aerospace and high-performance sports equipment.
• Ti-3Al-8V-6Cr-4Mo-4Zr: Very high strength and toughness can be offered by this material; it is mainly applied to high load aerospace structural parts and deep-sea equipment.
• Ti-15V-3Cr-3Al-3Sn: Very high strength and hardness make this alloy useful for highly stressed components in aerospace and military uses.

4. α+β-type Titanium Alloy Powders

These are a combination of α-phase and β-phase and thus have advantages of both types. Therefore, the α+β-type titanium alloy powders are of very excellent comprehensive properties and are applicable in a wide range of fields.

• Ti-6Al-4V Grade 5: This is the most applied titanium alloy, containing 6% aluminum and 4% vanadium. Grade 5 has the merits of high strength, good corrosion resistance, and light weight. Therefore, it has many uses in the aerospace, medical, automotive, and marine engineering fields.
• Ti-6Al-2Sn-2Zr-2Mo-2Cr: Known for its good weldability and overall mechanical properties, it is commonly used in aerospace structures and turbine engine parts.

Fig 2. The crystal structure of α phase (hcp) and the allotropic β phase structure (bcc)

Table 1. Types of Titanium-based Powders

For the commercial and industrial fields, Stanford Advanced Materials has been committed to supplying customers with various kinds of spherical alloy powders; among them are different sorts of titanium-based powders. You can go directly to check the details of the different sorts of titanium alloy powders in the above table by clicking the relative links. You can also get details about the products here: Titanium Based Powder.

Titanium Grade 2 vs Grade 5: Which is Better

Titanium Grade 2 and Grade 5 are compared frequently because they are among the most widely used materials in the titanium and titanium alloy family. Comparing them helps in understanding the right material choice for different application scenarios.

1. Titanium Grade 2 vs Grade 5: Composition comparison

Grade 2 is relatively free from impurity elements and, hence, is considered good in corrosion resistance and ductility. The addition of 6% aluminum and 4% vanadium greatly enhances the strength and hardness of the material without sacrificing the properties of corrosion resistance in grade 5.

Table 2. Composition Comparison of Grade 2 and Grade 5

2. Titanium Grade 2 vs Grade 5: Properties Comparison

Table 3. Properties Comparison of Grade 2 and Grade 5

We can conclude the following from the Table 3:

• Tensile Strength and Yield Strength: Grade 5 has much higher strength due to aluminum and vanadium's addition in it than Grade 2, and therefore, finds the largest application advantages as high-strength low-weight material in almost every type of engineering field.
• Elongation: Grade 2 has more elongation, which will allow it to have better plasticity when in the process of forming.
• Density: The two grades have similar densities. However, due to its high strength, Grade 5 becomes the better option for uses that truly depend on high-strength and light weight
• Corrosion Resistance: Grade 2 has outstanding corrosion resistance, but Grade 2 is superb in extremely aggressive kinds of media.
• Thermal-Conductivity and Electrical Conductivity: Grade 2 has higher thermal-conductivity and electrical conductivity, suiting the applications that need thermal or electrical conductivity.
• Weldability and Workability: Grade 2 has higher workability and welds more easily relative to Grade 5, which is extremely difficult to weld and work because of its high strength and hardness.

3. Titanium Grade 2 vs Grade 5: Application Comparison

The applications of Titanium Grade 2 and Grade 5 vary across different industries. Grade 2 is commercially pure titanium, which is usually applied in large quantities in chemical equipment, marine engineering, and medical appliances such as surgical instruments or implants due to excellent corrosion resistance and good ductility, and it also includes pipes and heat exchangers.

On the other hand, Grade 5 is a high-strength titanium alloy mainly applied in aerospace, as in aircraft fuselage and engine parts; in high-performance automotive parts; in medical implants, such as bone plates and prostheses of joints; and military equipment since it has an excellent strength-to-weight ratio with good corrosion resistance.

4. Titanium Grade 2 vs Grade 5: Cost Comparison

Grade 2 is generally easier to process, and weld, and less expensive than Grade 5. That may help save huge costs when large-scale production and complicated shapes are required. It should not be said that while Grade 5 is more processing difficult and expensive, high strength and lightweight advantages might be very helpful to bring more benefit in its overall performance for some very demanding high performance-oriented applications.

Conclusion

In other words, the choice between Titanium Grade 2 and Grade 5 is always based on the requirements of the application. Grade 2, due to better corrosion resistance, workability, and cost value, will be preferred where these properties are of importance—like in chemical processing and marine applications. On the other side, Grade 5 shows an excellent strength-to-weight ratio and is a high-performance metal; it finds optimum applications in stringent industries like aerospace, medical implants, and high-performance automotive parts. Knowing these differences allows for making a more informed selection of materials to ensure that optimal performance is reached in their respective industrial applications.

For the commercial and industrial fields, Stanford Advanced Materials has been committed to supplying customers with various kinds of spherical alloy powders; among them are different sorts of titanium-based powders. You can go directly to check the details of the different sorts of titanium alloy powders in the above table by clicking the relative links. You can also get details about the products here: Titanium Based Powder.

Related articles:

Demystifying Titanium Alloys: Ti 6-4 Grade 5 vs. Ti 23

Reference:

[1]. Janzeer, Yasmeen. (2013). SURFACE MODIFICATION OF TITANIUM AND TITANIUM ALLOYS TO ENHANCE BONE HEALING. 10.13140/RG.2.1.4790.1042.