Microhardness

microhardness

[¦mī·krō′härd·nəs]
(metallurgy)
Hardness of microscopic areas of a metal or alloy.

Microhardness

 

the hardness of individual segments of the microstructure of a material.

The microhardness is measured by pressing with a diamond pyramid under a load of less than 2 newtons (200 grams-force). The size of the mark produced is measured under a microscope, and the hardness number—the ratio of the applied pressure to the surface area of the mark—is calculated using special tables. The instrument for determining microhardness permits selection of a particular segment of the microstructure onto which the diamond will be pressed. Such selection, as well as the small size of the marks produced, makes possible measurement of the microhardness of crystals of individual phases or various segments of a grain.

Data on microhardness are used in studying plastic deformations and the nonuniformity of distribution of dissolved impurities along the grain, as well as for plotting phase equilibrium diagrams.

References in periodicals archive ?
Tenders are invited for Vickers microhardness hardness tester - 2019/0127
These acids have been shown to have damaging effects on the polymer network of RBC resin adversely affecting their physical properties including; microhardness.11
The fracture morphology and the microhardness distribution of double-pass joint have been examined by Li et.
The samples for Vickers microhardness testing are cut into rectangular strips (36 x 6.35 x 6 mm) from welded plates from the centerline along the transverse cross section.
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This lead to fibrous morphology of COC in HDPE matrices and strong improvements in mechanical performance: the values of elastic modulus, yield strength and microhardness as a function of COC content were above the predictions based on equivalent box model [2, 9] and the tensile energy to break showed a synergistic improvement, exceeding the values of the individual components.
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Also a significant increase of the microhardness (2 times) of the samples was observed for the composite with 40 wt% PSD.
For Vickers microhardness testing 10 disks of each cement specimen was exposed to 100 grams of load for 15 seconds.
The following parameters were adopted as response ones: high-altitude roughness characteristics Ra, Rz and microhardness H[mu], characterising the quality of the machined surface.
There have been studies investigating microhardness as well as properties such as the biocompatibility of calcium silicate-based sealers.
A microhardness tester (MH-3) was used to measure the microhardness distribution across the cross-section of 20CrMnTi pins against the chroming and nonchroming T10 steel discs using a Vickers indenter under a load of HV0.01 with a dwell time of 20 s.