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 ?
The hardness was measured by a microhardness testing tester (PMT-3) with a load of 100 gf.
Tenders are invited for Supply of microhardness tester etc.
The microhardness was measured by penetrating a diamond pyramid indenter under a load of 200 gf for 10 sec onto the surface of composite.
Vickers microhardness was measured for all castings starting from the alpha-case layer down to the base metal, where the hardness flattens out.
Surface gloss can be evaluated together with microhardness as both of these characteristics describe the surface properties.
Microhardness Testing of Automotive Coatings--Mei Wen, Axalta Coatings Systems (Gordon Award competition paper)
The Vickers microhardness data discussed in this study were obtained using Leco Microhardness Tester machine.
Microhardness readings were taken and were much higher than expected.
In addition, results obtained from the measurement of pressure and microhardness properties at environment temperature showed that as the structure of particles becomes smaller in size and as nanoparticles are added up to four volume percent, significant increase is observed in the strength up to five times and three times in hardness in comparison to copper particles at micrometric scale.
Other topics of the 64 selected papers include the influence of loading conditions on the deformation behavior of human enamel studied by instrumented indentation, using microhardness to determine the fracture stress of ultra-high-strength ribbons, mechanical properties of the interface in heterogeneous diffusion welds on titanium and austenitic steel, a modulus mapping test to characterize the interphase in polymeric composite reinforced by carbon fiber, and verifying a numerical model for trabecular tissue using a compression test and time-lapse X-ray radiography based on a material model determined from a three-point bending test of a single trabecula.
measurement and analysis of microhardness distribution in the coating section;
Ni-P electrodeposits with low P content in the range of 4-7 wt% of P exhibited superior microhardness of 7.