INCOLOY Alloy 908 (UNS N09908)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Applications

Introduction

Incoloy alloy 908 is a nickel-iron alloy that has high tensile strength, fatigue crack growth resistance, good weldability, metallurgical stability and ductility, high fracture and impact toughness, low coefficient of thermal expansion, and resistance to oxygen embrittlement, which allows hot fabrication without cracking.

The following section will discuss in detail about Incoloy alloy 908.

Chemical Composition

The chemical composition Incoloy alloy 908 is outlined in the following table.

Element Content (%)
Nickel, Ni 47 - 51
Iron, Fe 35.588 - 44.6
Chromium, Cr 3.75 - 4.5
Niobium, Nb (Columbium, Cb) 2.7 - 3.3
Titanium, Ti 1.2 - 1.8
Manganese, Mn ≤1
Aluminum, Al 0.75 - 1.25
Cobalt, Co ≤0.50
Copper, Cu ≤0.50
Silicon, Si ≤0.50
Carbon, C ≤0.030
Phosphorous, P ≤0.015
Boron, B ≤0.012
Sulfur, S ≤0.0050

Physical Properties

The following table shows the physical properties of Incoloy alloy 908.

Properties Metric Imperial
Density 8.17 g/cm3 0.295 lb/in3
Melting point 1361-1410°C 2482-2570°F

Mechanical Properties

The mechanical properties of Incoloy alloy 908 are displayed in the following table.

Properties Metric Imperial
Tensile strength 1172 MPa 170000 psi
Yield strength 827 MPa 120000 psi
Elongation at break 12% 12%

Thermal Properties

The thermal properties of Incoloy alloy 908 are given in the following table

Properties Metric Imperial
Thermal expansion co-efficient (@93°C/199°F) 8.59 µm/m°C 4.77 µin/in°F
Thermal conductivity 11.05 W/mK 76.69 BTU.in/hrft².°F

Other Designations

An equivalent material to Incoloy alloy 908 includes ASTM B 872.

Applications

The following are the list of applications of Incoloy alloy 908:

  • Prototype fusion reactors
  • High-strength cryogenic applications.

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