What is AMS 4881 / C95520?
AMS 4881 is an American specification for a very high strength cast nickel aluminium bronze, also designated UNS C95520. It has very high anti-galling properties against most grades of steel and is used universally for aerospace landing gear bushes and bearings. It is one of the highest strength aluminium bronzes available, is beryllium-free, and is a realistic alternative to copper beryllium for high load applications.
Should you specify AMS 4881 / C95520?
Specify AMS 4881 or C95520 when the bearing load is high, the frequency is relatively low, and strength matters more than ductility. Typical continuous cast values are 860 MPa UTS and 621 MPa 0.2 % yield, with 2 % elongation.
The strongest commercial argument for this grade is that it is beryllium-free. It is presented as a realistic alternative to copper beryllium for high load applications, without the environmental or health and safety issues associated with beryllium-bearing alloys.
Where you need more ductility from a cast aerospace bush, AMS 4880 gives 9-12 % elongation instead of 2 %. Where you need a wrought product rather than a casting, C63020 to AMS 4590 covers similar strength territory.
As with AMS 4880, casting route matters: sand, centrifugal and continuous casting are all allowed, and continuous casting gives the best combination of reliability, quality and efficiency. Published properties are for material quench hardened at 871-927 °C and temper annealed at 496-538 °C.
Best for relatively low frequency, high load heavy-duty bearing applications, and where a beryllium-free replacement for copper beryllium is required.
AMS 4881 / C95520 quick reference
Typical, indicative values as published by Copper Alloys Ltd. Typical values are not specification limits, and vary with product form, section size and temper.
| Alloy type | Cast - Cast nickel aluminium bronze |
|---|---|
| Nominal composition | CuAl11Ni5Fe5 |
| Tensile strength (typical) | 860 MPa (124 ksi, continuous cast) |
| Proof / yield strength (typical) | 621 MPa (0.2 %, 91 - 105 ksi) |
| Elongation (typical) | 2 % |
| Hardness (typical) | 200 HB (C95520 datasheet) |
| Izod impact (typical) | Not published |
AMS 4881 / C95520 typical mechanical properties
| Form | Size range | Yield 0.2% (MPa) | UTS (MPa) | Elong % |
|---|---|---|---|---|
| Continuous cast | All sizes | 621 | 860 | 2 |
Quench hardened 871-927 °C (1600-1700 °F) and temper annealed 496-538 °C (925-1000 °F).
C95520 datasheet typical values: tensile 870 N/mm², proof 660 N/mm², elongation 5 %, hardness 200 HB.
AMS 4881 / C95520 typical physical properties
Key features of AMS 4881 / C95520
- Excellent wear resistance and anti-galling properties against steels and against itself, ideal for landing gear bushes and bearings.
- Very high strength, proven to last for decades in service.
- Beryllium-free, so there are no environmental or health and safety issues associated with its use.
- Heat treatable, suited to elevated temperature, with excellent resistance to corrosion and fatigue.
- Will not tolerate poor lubrication, poor alignment or dirty lubrication. Generally used against hardened steel shafts with a fine finish.
AMS 4881 / C95520 applications
Aerospace
- Bushes and bearings for landing gears
- Retractable spherical bearings for landing gear assemblies
Oil and gas
- Rock bit bearings
- Well head components
- Bushes and washers
Automotive and industrial equipment
- Bearings
- Off-road truck bushings
- Hydraulic bushes for earth moving equipment
- Tube forming tools
- Cryogenic applications
- Drill guide bushes
Military
- Aircraft bearings and bushes
- Tank track bearings
Marine
- Pump parts
- Hinge bearings and bushes
AMS 4881 / C95520 equivalent specifications
Frequently asked questions
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Information provided is for reference only
The composition, mechanical and physical figures on this page are typical, indicative values compiled from published Copper Alloys Ltd datasheets to aid early-stage material selection. They are not specification limits and are not engineering, procurement, safety, regulatory or design advice.
Before specifying, purchasing or using any material, confirm the requirements against the current controlled version of the relevant standard and obtain a certified material test report and written technical confirmation from Copper Alloys Ltd or another qualified foundry.