Grade 706 Zirconium (Zr-2.5Nb) Technical Data Sheet
Alloy Overview
Grade 706 Zirconium (Zr-2.5Nb) is a zirconium alloy containing 2.5% niobium (Nb) as the key alloying element, with strict controls on iron (Fe), chromium (Cr), hafnium (Hf), and oxygen (O). It offers a balance of mechanical strength and corrosion resistance, making it suitable for applications in demanding environments. The minimum zirconium content is 95.5% (including a maximum of 4.5% hafnium).
Chemical Composition (Weight %)
Component
Content Range
Zr (Zr + Hf)
Min 95.5 (balance)
Nb
2.5
Fe + Cr
0.2
Hf
Max 4.5
O
0.16
Physical Properties
Property
Metric
English
Density
6.44 g/cc
0.233 lb/in³
Mechanical Properties
Property
Metric
English
Notes
Tensile Strength (Ultimate)
Min 510 MPa
Min 74,000 psi
Tensile Strength (Yield, 0.2%)
Min 345 MPa
Min 50,000 psi
0.2% offset
Elongation at Break
20%
20%
Measured in 50 mm
Modulus of Elasticity
97.9 GPa
14,200 ksi
Poisson’s Ratio
0.33
0.33
Shear Modulus
34.5 GPa
5,000 ksi
Electrical Properties
Property
Metric
English
Electrical Resistivity
5.5e-005 ohm-cm
5.5e-005 ohm-cm
Thermal Properties
Property
Metric
English
Notes
Linear CTE (20°C)
6.3 μm/m-°C
3.5 μin/in-°F
Measured at 25°C
Specific Heat Capacity
0.285 J/g-°C
0.0681 BTU/lb-°F
Thermal Conductivity
17.1 W/m-K
119 BTU-in/hr-ft²-°F
Melting Point
1840°C
3340°F
Key Features & Applications
Corrosion Resistance: Excellent in aggressive environments (e.g., chemical processing, nuclear applications) due to zirconium’s natural oxide layer, enhanced by niobium addition.
Mechanical Strength: Balances high tensile strength and ductility, suitable for structural components under moderate stress.
Typical Uses: Nuclear reactor components, chemical processing equipment, and high-integrity piping/tubing where corrosion resistance and mechanical reliability are critical.
