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 Upgradation of leica microhardness tester model vmht mot sl.
Both bleaching systems significantly reduced microhardness of both composite groups.
The microstructural and microhardness analysis has been carried out for joint with maximum strength.
Microhardness measurements were performed on an AMH43 automated hardness indenter.
SUMMARY--The aim of the study was to determine microhardness of high- and low-viscosity bulk-fill composite resins and compare it with conventional composite materials.
Figure 7 shows the effect of the percentage of reinforcement and compaction pressure in each of the compounds on the microhardness, measured with "Vickers" scale, considering that this mechanical property can predict the behaviour of the sintered against wear resistance.
Recently [30] the microindentation or microhardness technique has been also very useful to elucidate the microstructure of multilayered systems based on blends of poly(ethylene terephthalate) (PET)/poly(ethylene naphthalene 2,6-dicarboxylate) (PEN)/clay nanocomposites.
This electronic processing of elements with optical ceramics without heating leads to increase their microhardness, streamline and strengthen the structure by forming the surface layers of compressive stresses and thereby to increase the strength of products to thermal shock effects, which they are exposed to in operation.
Interior and Surface Microhardness (Test Code: L1 and L5)
The trend of nanohardness and microhardness profiles in the intermediate area between the inner layers with constant hardness and abnormal area gives information on structural heterogeneity [14].
From the micromechanical point of view, measurements of Vickers microhardness and modulus of elasticity are carried out in a microhardness testing machine (CSM Instrument, Switzerland), using 100 g load applied for 20 s (dwell time).
This coating demonstrated enhanced hardness (pencil hardness = 7H and microhardness = 626 MPa) and toughness (excellent flexibility of 5 mm in the mandrel bend test).