NiTiHf Alloy Tube
Products Description
NiTiHf (nickel-titanium-hafnium) alloy is a new generation of high-temperature shape memory alloy (HTSMA) tubing developed by adding hafnium (Hf) to traditional binary NiTi shape memory alloys. By raising the phase transformation temperature, this alloy significantly extends the operating temperature range of NiTi alloys-pushing the upper limit from the conventional 100°C to over 300°C-thereby enabling its use in high-temperature actuation scenarios within aerospace and advanced industrial sectors.
NiTiHf alloy tubes are most commonly applied in the form of torque tubes; capable of directly converting thermal energy into mechanical torsional output, these tubes serve as critical actuating components for achieving lightweight designs and high power-to-weight actuation ratios in smart structures and adaptive systems.
Key Grade
Standard grade: Ni50.3Ti29.7Hf20
Currently, the most mature grade in terms of research and application is Ni50.3Ti29.7Hf20 (atomic percentage); the nickel content is slightly higher than the equiatomic ratio (nickel-rich design), which is key to achieving excellent performance.
Core Advantages
The core advantage of NiTiHf alloy tubing lies in overcoming the operating temperature limitations of traditional shape memory alloys. It achieves a balance of high torque output and high work density at elevated temperatures, making it a critical material for high-temperature actuation applications, such as in the aerospace industry.
High-Temperature Operating Capability
NiTiHf alloys can raise the phase transformation temperature to the 150–300°C range, or even beyond 450°C. Research has confirmed that the martensitic transformation start temperature (Ms) can exceed 750–800°C, truly establishing its status as an "Ultra-High-Temperature Shape Memory Alloy" (UHTSMA).
High Actuation Strain
Under pure torsion conditions, the phase transformation shear strain can reach approximately 6%.
Exceptional Torque and Work Output
Tubing with an outer diameter of 25.4 mm can withstand shear stresses up to 500 MPa, corresponding to a torque of 1,400 N·m and a work output of up to 27.5 J/cm³.
Significant Two-Way Shape Memory Effect (TWSME)
After minimal thermo-mechanical training (approximately 600 cycles), the material exhibits a stable two-way shear strain of 2.95% to 3.25%, with efficiency significantly superior to that of traditional NiTi alloys.
chemical composition
| Composition (at%) | Ni (at%) | Ti (at%) | Hf (at%) |
| Ni50.3Ti29.7Hf20 | 50.3 | 29.7 | 20 |
Physical Properties
The physical properties of NiTiHf alloys are influenced by composition and processing techniques; the following are reference ranges.
| Density | 6.5 - 7.0 g/cm³ |
| Thermal Conductivity | 15 - 19 W/(m·K) |
Mechanical properties
| Tensile Strength | ≥900 MPa - 1030 MPa |
| Yield Strength | ≥600 MPa |
| Hardness | HV 300 - 400 |
Large-scale production
Successful Scaled-Up Production: Research demonstrates that NiTiHf alloys can be successfully processed via industrial routes such as hot extrusion; standard tubing with an outer diameter of 25.4 mm has been produced from large-scale ingots, exhibiting actuation performance consistent with that of small-scale laboratory tubing. This lays the foundation for mass production.
Lork Group
Marketing Operations Department
Email: layla@lorkgroup.com
WhatsApp: +86 199 3707 5488
Hot Tags: NiTiHf, NiTiHf Alloy Tube, High-Temperature Shape Memory Alloy, NiTiHf Tube, NiTiHf Torque Tube, Ni50.3Ti29.7Hf20, UHTSMA
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