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.

Equivalent Materials



Density ρ

7.45 g/cm³ at 20 °C


Charpy impact energy aK,charpy

6.8 J at 20 °C

Compressive strength Rmc

1241 MPa at 20 °C

Compressive yield strength, 0.1% Rs,0.1

758 MPa at 20 °C

Elastic modulus E

124 GPa at 20 °C

Elongation A5 A5

6 % at 20 °C

Fatigue strength SNf

255 MPa at 20 °C

100.000.000 cycles

Hardness, HBW HBW

293 [-] at 20 °C

HBW 10/3000

Hardness, Rockwell C HRC

30 [-] at 20 °C

Reduction of area Z

5 % at 20 °C

Shear strength τ

552 MPa at 20 °C

Tensile strength Rm

930 MPa at 20 °C

Yield strength Rp0.5 Rp0.5

724 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 %






10.5 %


5 %


4.8 %


1.5 %


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, etc..

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.