Performance and analysis of recording microhardness tests

Abstract

With a microhardness arrangement which is constructed as an accessory equipment for modern material testing machines the generation of Vickers indentation is investigated by recording of the load during a programmed penetration of the pyramide. For all engineering materials investigated the relation between load L and penetration depth p could be fitted by L=a1p ± a2p2 with a high degree of statistical reliability. It is derived a new hardness number which is independent of the load also in the microhardness region. By comparison it can be shown that conventionally measured Vickers hardness numbers are identical for the ductile metals but to large for brittle materials. Furtheron it is possible to determine quantitatively the change of the hardness of the surface layer disturbed by mechanical polishing. By the same experiment it is investigated in microregions of the different materials the inelastic behaviour by stress relaxation and the elastic recovery by measurement of the L‐p relation during unloading.

Deformation of MgO by Vickers microindentation tests

“…The diagonals of the indentations d were measured for various loads P. Kick's law, P = ad2 [11] was verified for (100), (110) and (111) faces of NiO [8], CoO figure 3, together with results from the litterature.…”

Mechanical behavior of Ti cold spray coatings determined by a multi-scale indentation method

“…However, the technique has also been fraught with potential artifacts, many of which are related to a phenomenon known as the "indentation size effect" [2][3][4][5][6][7][8][9][10][11]. This typically refers to the simple observation that the hardness measured by an indentation test is often not constant, but instead changes with applied load.…”

Determination of Anodized Aluminum Material Characteristics by Means of Nano-Indentation Measurements

“…Its attractiveness stems largely from the fact that mechanical properties can be determined directly from indentation load and displacement measurements without the need to image the indentation impresssion. With high-resolution testing equipment, this facilitates the determination of properties at the micrometer and nanometre scales [9][10][11]. For this reason the method has become a primary technique for determining the mechanical properties of thin films without removing the film from the substrate and as well as for capturing small structural features [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”