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Results of investigations of and an improvement in GET 161–2001, the State Primary Standard of hardness of metals based on the Shore D scale, are presented. The process of improvement in the standard was carried out at the All-Russia Research Institute of Physicotechnical and Radio Measurements (VNIIFTRI)from 2016 to 2018 for the purpose of assuring the uniformity of measurements of hardness based on the Leeb scales. New hardness components, such as stands for reproduction of the hardness numbers in the Leeb scales, were developed and constructed. GET 161–2019, the State Primary Standard of the hardness of metals based on the Shore D scale and the Leeb scales, was approved. The metrological characteristics of GET 161–2019 were investigated and the budget of measurement uncertainty in reproduction of hardness numbers based on the Leeb scales was compiled.

A relative acoustic gas thermometry unit for reproducing and transmitting the unit of thermodynamic temperature, i.e., kelvin, in the low temperature range 4.2–80 K was developed and tested. The proposed apparatus differs from previously developed relative acoustic gas thermometry devices in terms of the dimensions of the main resonator unit. Reducing the size of the resonator (cavity diameter) allowed the mass of the cooled parts of the installation to be diminished by several times compared to the mass of such parts of the previously used installation. This significantly reduces the quantities of liquid helium and nitrogen necessary for cooling the resonator, as well as decreases the time of temperature stabilization and, accordingly, the measurement time. The results of verifying the operation of the main systems of the developed installation are presented.

Relative acoustic gas thermometry setup is described. Described setup was developed and tested in VNIIFTRI. The setup is designed for the measurement of thermodynamic temperature in low temperature range down to 4,2 K. Main part of the setup is resonator with reduced cavity diameter. Reduction of resonator dimension lead to several times reduction of cooled parts of the setup with respect to the setup previously developed in VNIIFTRI. This decreases liquid nitrogen and liquid helium consumption required for cooling of resonator. Moreover, reduction of the mass of cooling parts reduces time required for temperature stabilization and thus measurement time. In the work the tests’ results of operation of main parts of the setup are presented.

The article presents the results of studies to improve the National primary standard machine for hardness of metals on the shore D scale GET 161-2001, which were performed in FSUE “VNIIFTRI” from 2016 to 2018 in accordance with the technical task of Rosstandart.The improvement was carried out in order to ensure the uniformity of hardness measurements on the Leeb scales. The created new parts of the primary standard machine, which are settings for reproducing hardness numbers on the Leeb scales, are considered. Metrological characteristics of the upgraded and adopted National primary standard machine (GET 161-2019) were investigated, the budget of measurement uncertainty was calculated for reproducing hardness numbers on the Leeb scales.

We present the results of research on the improvement of GET 30-94, the State Primary Standard of hardness on the Rockwell and Super Rockwell scales. The upgraded nodes of the standard are presented, its metrological characteristics are improved, the budget of the measurement uncertainty is calculated for reproducing the hardness numbers on the Rockwell and Super Rockwell scales. In the process of improving the standard, 15 hardness scales, previously not used in Russia, were introduced. The approved the State Primary Standard of hardness on the scale of Rockwell and Super Rockwell GET 30-2018 corresponds to the best world analogues.

A difference was determined between temperature defined by International Temperature Scale (ITS-90) and thermodynamic temperature measured by relative acoustic gas thermometry at 79.0000 K and at 83.8058 K. Measurement were carried out using misaligned spherical acoustic resonator filled with helium at different pressures. The isotherms were fitted for four different acoustic modes simultaneously assuming the same thermal accommodation coefficient and third acoustic virial coefficient for all modes. Our measurements yield the following differences between the thermodynamic temperature T and ITS-90 temperature $$T_{90}$$: $$T-T_{90}=-4.81 \pm 1.02$$ mK at 83.9058 K and $$T-T_{90}=-4.47 \pm 0.97$$ mK at 79.0000 K.

Frequencies of acoustic and electromagnetic resonances were measured in a quasispherical acoustic resonator at the temperature of the triple point of water. The resonator was filled with helium 4He. Based on the analysis of experimental data, a value for the Boltzmann constant of kB = 1.380651·10–23 J·K–1 with uncertainty of 2.4 ppm was obtained.

The size hardness effects are studied via the micro- and nanoindentation methods over the wide range of the depth of print h (from dozens of nanometers to several dozen micrometers) for several classes of materials, such as ionic and covalent single crystals (sapphire, silicon, lithium fluoride); metals (single-crystal Al, polycrystalline Cu, Ni, and Nb); ceramics (high-strength nanostructured TZP-ceramic based on the natural zirconium dioxide–baddeleyite mineral); amorphous materials (fused quartz); and polymers (polycarbonate and polytetrafluoroethylene). As is shown, some of them possess severe size hardness effects, whereas the others reveal the weak ones or even a lack of these effects. The thermoactivation analysis is implemented, as well, and the activating and energy characteristics of local deformation processes induced by an indenter are compared with the dominant plasticity micromechanisms of the studied materials at different stages of the print formation and with the size peculiarities. The materials with low hardness coefficients and meeting the requirements of ISО 14577 and GOST R 8.748-2011 standards in the nanohardness measurements are highlighted, as well. In the established load ranges, these materials are the promising candidates for their use as reference samples, which are designed to ensure the uniformity of the hardness measurements at the nano- and microscales, as well as for calibrating and testing the nanoindentometers.

Studies of variations in the hardness of representative materials of different classes over broad ranges of loads and depths of indentation are carried out. The usability of these materials is demonstrated and boundaries on the ranges of use of hardness meters produced from these materials for calibration of nanoindentation instruments are established.

The national primary standard for hardness according to the Martens scales and indentation scales, GET 211-2014, has been created to ensure the uniformity of measurements of hardness in the area of instrumented indentation. Methods for measuring the hardness of materials widely used in the nano- and micro-ranges are discussed.

Information is provided on the stages of constructing a national primary standard for hardness based on the Martens and indentation scales to ensure the uniformity of measurement in the field of nanoindentation. The choice of materials for hardness gauges is substantiated experimentally.

Studies aimed at improving the national primary standard for the hardness of metals on the Vickers scale are reported. The range of applied loads is extended from 0.098 to 0.0098 N. A basis is established for the development of a new national hardness standard with nanoindentation at loads of less than 0.0098 N.