The patented process gives AMPCO® M4 mechanical properties beyond the range of commercial nickel-aluminium bronzes, comparable to beryllium copper at a lower cost and without the beryllium copper industrial hygiene requirements.



Density ρ

7.45 g/cm³ at 20 °C


Charpy impact energy aK,charpy

4 - 5 J at 20 °C

Compressive strength Rmc

1100 - 1200 MPa at 20 °C

Compressive yield strength, 0.1% Rs,0.1

680 - 720 MPa at 20 °C

Elastic modulus E

110 - 120 GPa at 20 °C

Elongation A5 A5

3 - 4 % at 20 °C

Fatigue strength SNf

240 - 250 MPa at 20 °C

100.000.000 cycles

Hardness, HBW HBW

250 - 260 [-] at 20 °C

HBW 10/3000

Hardness, Rockwell C HRC

25 - 26 [-] at 20 °C

Reduction of area Z

3 - 4 % at 20 °C

Shear strength τ

520 - 530 MPa at 20 °C

Tensile strength Rm

750 - 780 MPa at 20 °C

Yield strength Rp0.5 Rp0.5

420 - 460 MPa at 20 °C


Coefficient of thermal expansion α

1.6E-5 1/K at 20 °C

Specific heat capacity cp

450 J/(kg·K) at 20 °C

Thermal conductivity λ

42 W/(m·K) at 20 °C


Electrical conductivity σel

4.80E+6 S/m at 20 °C

Specific Electrical conductivity

8.2 % IACS

Chemical properties


Weight %





Technological properties

Application areas

AMPCO® M4 was initially developed as an aircraft specification alloy for gears in retractable landing assemblies, engine spacer bearings and other similar applications. It is rapidly growing in use where higher mechanical properties at elevated temperatures together with corrosion-resistant properties are required. Typical applications include aircraft landing gear bearings and bushings, bending dies (shoes and mandrels) for the tube bending industry, gear wheels and wear/guide plates, cores and cavities in plastic injection molds and so on...

This material data has been provided by AMPCO METAL.

All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.