Meyer hardness test vs brinell hardness test

The Meyer hardness test is a

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...

test based upon

projected area Projected area is the two dimensional area measurement of a three-dimensional object by projecting its shape on to an arbitrary plane. This is often used in mechanical engineering and architectural engineering related fields, specifically hardne ...

of an impression. The hardness,

H

, is defined as the maximum load,

P_\text

divided by the projected area of the indent,

A_\text

. :

H=\frac .

This is a more fundamental measurement of hardness than other hardness tests which are based on the surface area of an indentation. The principle behind the test is that the mean pressure required to test the material is the measurement of the hardness of the material. Units of megapascals (MPa) are frequently used for reporting Meyer hardness, but any unit of pressure can be used.. The test was originally defined for spherical indenters, but can be applied to any indenter shape. It is often the definition used in

nanoindentation Nanoindentation, also called instrumented indentation testing, is a variety of indentation hardness tests applied to small volumes. Indentation is perhaps the most commonly applied means of testing the mechanical properties of materials. The nanoi ...

testing. An advantage of the Meyer test is that it is less sensitive to the applied load, especially compared to the

Brinell hardness test The Brinell scale characterizes the indentation hardness of materials through the scale of penetration of an indenter, loaded on a material test-piece. It is one of several definitions of hardness in materials science. History Proposed by Swe ...

. For

cold work Cold is the presence of low temperature, especially in the atmosphere. In common usage, cold is often a subjective perception. A lower bound to temperature is absolute zero, defined as 0.00K on the Kelvin scale, an absolute thermodynamic ...

ed materials the Meyer hardness is relatively constant and independent of load, whereas for the Brinell hardness test it decreases with higher loads. For annealed materials the Meyer hardness increases continuously with load due to strain hardening. Based on

Meyer's law Meyer's law is an empirical relation between the size of a hardness test indentation and the load required to leave the indentation.. The formula was devised by Eugene Meyer of the Materials Testing Laboratory at the Imperial School of Technology, ...

hardness values from this test can be converted into

Brinell hardness The Brinell scale characterizes the indentation hardness of materials through the scale of penetration of an indenter, loaded on a material test-piece. It is one of several definitions of hardness in materials science. History Proposed by Sw ...

values, and vice versa. The Meyer hardness test was devised by Eugene Meyer of the Materials Testing Laboratory at the Imperial School of Technology,

Charlottenburg Charlottenburg () is a Boroughs and localities of Berlin, locality of Berlin within the borough of Charlottenburg-Wilmersdorf. Established as a German town law, town in 1705 and named after Sophia Charlotte of Hanover, Queen consort of Kingdom ...

, Germany, circa 1908.V.E. Lysaght, ''Indentation Hardness Testing'', New York: Reinhold Publishing Corp., 1949, p 39-47.

References

Bibliography

*. Hardness tests {{mech-engineering-stub

See also

References

Bibliography