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 method to measure the hardness of materials. 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 the questioned material's ability to resist plastic deformation from a standard source. The Vickers test can be used for all metals 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 pascals, but should not be confused with a pressure, which also has units of pascals. 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 a pressure.
The hardness number is not really a true property of the material and is an empirical value that should be seen in conjunction with the experimental methods and hardness scale used.
Read more about Vickers Hardness Test: Implementation, Precautions, Estimating Yield Strength, Example of Use
Famous quotes containing the words hardness and/or test:
“Despots play their part in the works of thinkers. Fettered words are terrible words. The writer doubles and trebles the power of his writing when a ruler imposes silence on the people. Something emerges from that enforced silence, a mysterious fullness which filters through and becomes steely in the thought. Repression in history leads to conciseness in the historian, and the rocklike hardness of much celebrated prose is due to the tempering of the tyrant.”
—Victor Hugo (18021885)
“It is commonly said ... that ridicule is the best test of truth; for that it will not stick where it is not just. I deny it. A truth learned in a certain light, and attacked in certain words, by men of wit and humour, may, and often doth, become ridiculous, at least so far, that the truth is only remembered and repeated for the sake of the ridicule.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (16941773)