Composition and Key Properties
Grade 5 titanium, commonly known as Ti-6Al-4V, is an alpha-beta titanium alloy containing nominally 6% aluminum and 4% vanadium. It is called the workhorse titanium alloy because it accounts for the majority of titanium used worldwide, combining high specific strength, light weight, good formability and excellent corrosion resistance.
| Parameter | Typical Value (Grade 5) |
|---|---|
| Aluminum (Al) | 5.5-6.75% |
| Vanadium (V) | 3.5-4.5% |
| Iron (Fe), max | 0.40% |
| Oxygen (O), max | 0.20% |
| Titanium (Ti) | Balance |
| Density | About 4.43 g/cm³ |
| Tensile strength (typical minimum) | About 895 MPa (AMS 4928) |
| Yield strength (typical minimum) | About 828 MPa (AMS 4928) |
Product Forms and Applicable Standards
Ti-6Al-4V Grade 5 is supplied in a range of mill forms, each covered by specific specifications. The lists below reflect the commonly referenced standards for each form.
| Product Form | Applicable Specifications |
|---|---|
| Round rod | AMS 2631, AMS 4928, AMS 4965, AMS 6930, AMS 6931, AMS-T-9047; ASTM B348; ASME SB-381 |
| Rectangular rod | AMS 4928, AMS 4965, AMS 6930, AMS 6931, AMS-T-9047; ASTM B348 |
| Plate | AMS 2631, AMS 4911, AMS-T-9046; ASTM B265 Gr 5; EN 10204 3.1 |
| Block | AMS 4928, AMS 6931, AMS-STD-9047; ASTM B348 |
For medical implant applications, additional specifications such as ASTM F1472 apply to wrought Ti-6Al-4V.
Why Grade 5 Dominates Titanium Applications
The combination of roughly 45% lower density than steel with strength comparable to many steels makes Ti-6Al-4V attractive wherever weight saving matters. Its corrosion resistance in seawater and industrial atmospheres, together with good fatigue performance and the ability to be forged, rolled, machined and welded within controlled process windows, explains its dominance in demanding markets.
Application Sectors
Aerospace - airframe structures, fasteners, engine components and landing gear parts.
Medical - surgical implants and instruments, often specified to ASTM F1472 for implantable hardware.
Marine - shafts, fasteners and equipment exposed to seawater.
Industrial - chemical processing equipment, heat exchangers and power generation components.
Consumer and automotive - high-performance fasteners, racing components and sports equipment.
Specification and Procurement Considerations
When purchasing Ti-6Al-4V Grade 5, buyers should verify the product form and applicable specification, request a mill test certificate (for example EN 10204 3.1), and check that chemistry, mechanical properties and, where relevant, ultrasonic inspection (AMS 2631) comply with the ordered standard. Confirm the surface condition and dimensions against the drawing or machining allowance before processing.
Frequently Asked Questions
Q1: What is Grade 5 titanium 6Al-4V?
It is the most widely used titanium alloy, containing about 6% aluminum and 4% vanadium, with a balance of titanium.
Q2: What are the typical mechanical properties of Ti-6Al-4V?
Typical minimum tensile and yield strengths are about 895 MPa and 828 MPa respectively, with a density of about 4.43 g/cm³.
Q3: Which specifications cover Ti-6Al-4V round rod?
Round rod is commonly specified to AMS 2631, AMS 4928, AMS 4965, AMS 6930, AMS 6931 or AMS-T-9047, ASTM B348 and ASME SB-381.
Q4: Which standard applies to Ti-6Al-4V plate?
Plate is commonly specified to AMS 2631, AMS 4911, AMS-T-9046, ASTM B265 Grade 5 and EN 10204 3.1.
Q5: Why is Ti-6Al-4V used in medical implants?
Because it combines high strength, corrosion resistance, biocompatibility and a lower elastic modulus than stainless steel, reducing stress shielding.
Q6: Is Ti-6Al-4V weldable?
It can be welded under controlled conditions (clean environment, inert gas shielding, appropriate filler), but welding must be followed by suitable heat treatment to restore properties.