Papers by Keyword: Depth Sensing Indentation

Abstract: New technologies known as unconventional technologies make it possible to cut complex shapes at high speed and with relatively high precision. In many cases, especially in the case of thin sheet, created parts produced do not require any further treatment by post-machining. Knowledge of the accompanying phenomena, such as the heat-affected zone (HAZ) or the surface quality of the cutting edge, is necessary, for example, to assess further machining of material in these areas (e.g. drilling and reaming holes or finishing operations on the cutting edge). In this study, the thermal effect of four unconventional cutting technologies – laser, plasma, wire electrical discharge machining (wire EDM) and waterjet cutting on the cut surface of steel sheets is investigated. Steel 1.7102 (DIN 54SiCr6) was chosen for purpose of this study. The width of the HAZ and the nanohardness beneath the cut surface were analyzed.

Abstract: Nanomechanical testing using depth sensing indentation (DSI) provides a straightforward solution for characterizing of mechanical properties (indentation hardness H_IT, Young’s modulus E_IT, indentation energy: total W_total, elastic W_elast, plastic W_plast) of homogeneous (bulk) materials. However, real materials such as multi-phase steels are a heterogeneous material on the microscopic scale (microstructure). We need to know the local mechanical properties of each phase separately in those materials for reasons development of new materials and for modeling. Mechanical properties of each phase separately in multiphase materials are difficult or even impossible to examine in bulk material ex situ.In this paper we describe the technique for measuring the mechanical properties of each phase separately in multiphase steel by two-dimensional mapping tool. This approach relies on large arrays of nanoindentations (known as grid indentation) and statistical analysis of the resulting data [1, 2]. The aim of this investigation is to optimize the parameters of the grid indentation for a given microstructure of steel sheets.

Abstract: The influence of beta radiation on the changes in the structure and selected properties (mechanical and thermal) was proved. Using high doses of beta radiation for glass fiber filled polyamide (PA) and its influence on the changes of micromechanical properties of surface layer has not been studied in detail so far. The specimens of glass fiber filled PA were made by injection moulding technology and irradiated by low doses of beta radiation (0, 132, 165 and 198 kGy). The changes in the microstructure and micromechanical properties of surface layer were evaluated using WAXS and instrumented microhardness test. The results of the measurements showed change some in micromechanical properties (indentation hardness) when high doses of beta radiation are used.

Abstract: The main goal of this paper is to compare measurements of creep behavior of Crosslinking polymer materials. Creep properties have been measured by two methods, first is micro-indentation with Depth Sensing Indention (DSI) and the second method is long-term creep test in room temperature. By using of these principally different methods can be better analyzed the influence of radiation netting, and therefore better suggest an appropriate dose of radiation with respect to use of polymer material in practice. The evaluation criteria for DSI test is index CIT [%]. The evaluation criteria for the standard creep test is value of average elongation at the end of the test. Comparison of these two values shows slight influence of radiation dose with using the standard creep test instead of using micro-indentation creep test, which shows very slight influence of radiation dose on material.

Abstract: In this paper, the effect of the electron beam irradiation on the indentation hardness, indentation modulus and indentation creep have been studied by means of the Depth sensing indentation (DSI). Cross-linking is a process in which polymer chains are associated through chemical bonds. Radiation doses of 33, 66 and 99 kGy were used for unfilled polyamide 6 with the 7% crosslinking agent (triallyl isocyanurate). Beta irradiation of the examined thermoplastic caused the growth of values of material parameters as micro-hardness, indentation modulus or indentation creep etc. From this point of view, there may be new application in areas with mechanical properties higher than their original properties. This study compared the mechanical properties of irradiated and non-irradiated PA6.

Abstract: The paper presents an experimental study of the effect of beta radiation on nanomechanical properties of surface layer of PBT. Irradiation of polymers initiates cross-linking process in the structure especially in nanolayers. Applied radiation doses (66, 132 and 198 kGy) caused different nanomechanical changes which have a significant effect on the final properties of the tested PBT. Beta irradiation of the examined thermoplastic caused the growth of values of material parameters as nanoindentation hardness, nanoindentation modulus or deformation work. The improvement of nanomechanical properties was measured by the nanoindentation test.

Abstract: This article deals with the influence of different doses of Beta radiation on nanomechanical properties of High-density polyethylene (HDPE). These nanomechanical properties were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation. The highest values of nanomechanical properties were reached at radiation dose of 99 kGy, when the nanohardness values increased by about 23%. The purpose of the article is to consider to what extent the irradiation process influences the resulting nanomechanical properties measured by the Depth Sensing Indentation method.

Abstract: The presented article deals with the research of micro-mechanical properties in the surface layer of modified Polyamide 66 filled by 30% of glass fibers. These micro-mechanical properties were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation. Radiation doses used were 0, 15, 30 and 45 kGy for filled Polyamide 66 with the 6% cross-linking agent (triallyl isocyanurate). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the polyamide 66 tested. The highest values of micro-mechanical properties were reached at radiation dose of 30 kGy, when the micro-hardness values increased by about 64%. The aim of the article is to find out the influence of the radiation on the micro-hardness of the modified glass fiber-filled Polyamide 66 (PA66).