Editing Vickers hardness test (section)

{{Short description|Hardness test}}
{{Use dmy dates|date=April 2022}}
[[File:Vickers-tester.jpg|thumb|A Vickers hardness tester]]

The '''Vickers hardness test''' was developed in 1921 by Robert L. Smith and George E. Sandland at [[Vickers Ltd]] as an alternative to the [[Brinell scale|Brinell]] method to measure the [[hardness]] of materials.<ref>R.L. Smith & G.E. Sandland, "An Accurate Method of Determining the Hardness of Metals, with Particular Reference to Those of a High Degree of Hardness," ''[[Proceedings of the Institution of Mechanical Engineers]]'', Vol. I, 1922, p 623–641.</ref> The Vickers test is often easier to use than other hardness tests since the required calculations are independent of the size of the indenter, and the indenter can be used for all materials irrespective of hardness. The basic principle, as with all common measures of hardness, is to observe a material's ability to resist [[plastic deformation]] from a standard source. 
The Vickers test can be used for all [[metal]]s and has one of the widest scales among hardness tests. 
The unit of hardness given by the test is known as the '''Vickers Pyramid Number''' ('''HV''') or '''Diamond Pyramid Hardness''' ('''DPH'''). The hardness number can be converted into units of [[pascal (unit)|pascals]], but should not be confused with [[pressure]], which uses the same units. The hardness number is determined by the load over the surface area of the indentation and not the area normal to the force, and is therefore not pressure.