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Indentation hardness tests compose the majority of processes used to determine material hardness, and can be divided into three classes: macro, micro and nanoindentation tests. [2] [3] Microindentation tests typically have forces less than 2 N (0.45 lb f). Hardness, however, cannot be considered to be a fundamental material property.
A Rockwell hardness tester. The Rockwell hardness test is a hardness test based on indentation hardness of a material. The Rockwell test measures the depth of penetration of an indenter under a large load (major load) compared to the penetration made by a preload (minor load). [1]
If Meyer's index is greater than 2.2, then the ratio increases. [1] The Brinell hardness is designated by the most commonly used test standards (ASTM E10-14 [2] and ISO 6506–1:2005) as HBW (H from hardness, B from brinell and W from the material of the indenter, tungsten (wolfram) carbide). In former standards HB or HBS were used to refer to ...
The indentation size effect (ISE) is the observation that hardness tends to increase as the indent size decreases at small scales. [1] [2] When an indent (any small mark, but usually made with a special tool) is created during material testing, the hardness of the material is not constant. At the small scale, materials will actually be harder ...
Most recently, Jha et al. [3] found that the Korsunsky work-of-indentation approach measures the nominal hardness of a material which is defined as the maximum load divided by the area of maximum contact. The nominal hardness of a material is different than its true hardness (determined by the Oliver-Pharr method), but the two concepts are ...
The Barcol hardness test is generally used on soft materials such as rigid plastics. It measures hardness based on indentation of a sharp point with a flat tip. The test is performed using a similar method and indentation device as that used to measure Shore D hardness, however the Shore D indentor has a round tip. [4]
L is the length of indentation along its long axis C p is the correction factor related to the shape of the indenter, ideally 0.070279 P is the load. HK values are typically in the range from 100 to 1000, when specified in the conventional units of kg f ⋅mm −2. The SI unit, pascal, is sometimes used instead: 1 kg f ⋅mm −2 = 9.80665 MPa.
The specific heat of pure water is ~ 1 calorie per gram, the specific heat of dry soil is ~ 0.2 calories per gram, hence, the specific heat of wet soil is ~ 0.2 to 1 calories per gram (0.8 to 4.2 kJ per kilogram). [90] Also, a tremendous energy (~584 cal/g or 2442 kJ/kg at 25 °C) is required to evaporate water (known as the heat of ...