What is TC11 (Ti-6.5Al-3.5Mo-1.5Zr-0.3Si)?
Ti-6.5Al-3.5Mo-1.5Zr-0.3Si is a high-performance near-alpha titanium alloy widely used in aerospace, medical devices, CNC machining, and industrial applications. This comprehensive guide covers its chemical composition, mechanical properties, machining characteristics, and practical applications per ASTM/GB standards.
Chemical Composition
| Element | Content (%) | Standard |
|---|---|---|
| Primary Element | Balance | ASTM/GB |
| Alloying Elements | Per specification | ASTM/GB |
| Impurities (max) | ≤0.1% | ASTM |
Mechanical Properties
| Property | Value | Standard |
|---|---|---|
| Tensile Strength | ≥500 MPa | ASTM |
| Yield Strength (0.2% offset) | ≥300 MPa | ASTM |
| Elongation | ≥15% | ASTM |
| Hardness | 200 HV / 95 HRB | ASTM |
Key Features
- Excellent mechanical properties: High strength-to-weight ratio, suitable for lightweight design
- Good corrosion resistance: Resistant to seawater, acids, alkalis, and industrial atmospheres
- Superior machinability: Excellent CNC machining characteristics with proper tooling
- Wide temperature range: Maintains properties from cryogenic to elevated temperatures
- Biocompatible: Safe for medical and food processing applications
Common Applications
- Aerospace: Aircraft structural components, engine parts, landing gear, fasteners
- Automotive: High-performance engine components, suspension parts, exhaust systems
- Medical devices: Surgical instruments, implants, dental equipment, MRI-compatible components
- Industrial equipment: Pump components, valve bodies, heat exchangers, chemical processing equipment
- Consumer products: High-end EDC tools, watch cases, bicycle components, sporting goods
CNC Machining Guidelines
Tool Selection
- Tool material: Carbide (YG/YW class) or coated carbide for optimal performance
- Tool geometry: Positive rake angle (5-15°), relief angle (8-12°)
- Nose radius: 0.4-0.8mm for fine finishing, 0.8-1.2mm for roughing
Recommended Cutting Parameters
| Operation | Cutting Speed (m/min) | Feed Rate (mm/rev) | Depth of Cut (mm) |
|---|---|---|---|
| Rough Turning | 80-120 | 0.2-0.4 | 2-4 |
| Finish Turning | 120-180 | 0.05-0.15 | 0.2-0.5 |
| Milling | 100-150 | 0.1-0.3 | 1-3 |
| Drilling | 60-100 | 0.1-0.2 | N/A |
Coolant & Lubrication
- Coolant type: Emulsion or synthetic coolant with EP additives
- Coolant pressure: ≥5 MPa, directed at cutting zone
- Avoid dry cutting: Always use coolant to prevent work hardening and tool wear
Heat Treatment (if applicable)
- Annealing: 650-750°C, air cool or furnace cool
- Solution treating: Per material specification
- Aging: As required for precipitation hardening alloys
Surface Finish Options
- As-machined: Ra 1.6-3.2 μm
- Fine turning: Ra 0.8-1.6 μm
- Polishing: Ra 0.2-0.4 μm (mirror finish)
- Bead blasting: Uniform matte finish
- Anodizing: For titanium alloys (various colors)