The draft of part 5 of ISO 14577 specifies verification and calibration of testing machines for c... more The draft of part 5 of ISO 14577 specifies verification and calibration of testing machines for carrying out the measurement of the dynamic material response when an oscillatory force or displacement, with amplitudes small in comparison to the prescribed target values, is imparted to the indenter while the indenter is continuously loaded to a prescribed target load or target depth or while the load or displacement is held constant at a prescribed target value. In case of a material showing plastic-elastic behavior, the measured dynamic response is used for continuous evaluation of the dynamic stiffness of the contact as a function of depth and frequency. Using the dynamic stiffness of the contact a reduced dynamic modulus will be calculated. In case of a material showing visco-elastic behavior from the measured dynamic response also the dynamic contact damping coefficient as function of depth and frequency is evaluated continuously. Using dynamic contact stiffness and dynamic contact damping coefficient reduced lost and storage modulus for visco-elastic materials will be calculated. The main normative requirements of the draft are discussed and their applications are illustrated by examples from daily experimental praxis.
International Journal of Materials Research, Nov 1, 2005
An extensive comparison between the conventional Vickers hardness at 500 mN and indentation hardn... more An extensive comparison between the conventional Vickers hardness at 500 mN and indentation hardness measured with Vickers indenters at 500 mN is presented for up to 20 different materials and for three different instruments. Additionally, the indentation modulus is compared to Young’s modulus, which was measured with alternative methods or taken from the literature. It is shown that the agreement between the results from depth-sensing indentation and the reference values can be improved by additional corrections, for the calculation of the indentation area. With corrections the mean hardness difference to the Vickers hardness reference as average of all investigated materials can be reduced to about 10 % although disturbing pile-up or sink-in effects can still not be considered. For the modulus, the mean difference was only about 6 %.
Focal adhesion contact formation by fibroblasts cultured on surface-modified dental implants: an ... more Focal adhesion contact formation by fibroblasts cultured on surface-modified dental implants: an in vitro study Birte Größner-Schreiber
Do different implant surfaces exposed in the oral cavity of humans show different biofilm composi... more Do different implant surfaces exposed in the oral cavity of humans show different biofilm compositions and activities?
The ISO/DIS 14577 Metallic materials - Instrumented indentation test for hardness and materials p... more The ISO/DIS 14577 Metallic materials - Instrumented indentation test for hardness and materials parameters Part 1-3 (IIT) concerns test forces up to 30 kN. The paper reports on IIT at test forces ranging from 0.002 N to 1000 N on non magnetizable steel X8 CrMnN 18- 18 (1.386) with well polished surface using Vickers indenter and four hardness machines of different design (Nano Indenter XP, Fischerscope H 100, Zwick Z005 with Universal hardness head and a laboratory four-column set up materials testing machine) according to the standard. Using mostly identical test parameters the results of the different machines are almost in good agreement. Estimated small differences are caused by the different uncertainties of the used machines and by different methods of mathematical analysis of the detected raw data.
Polycrystalline Ni materials with grain sizes less than 100 nm (nano crystalline NC) and with gra... more Polycrystalline Ni materials with grain sizes less than 100 nm (nano crystalline NC) and with grain sizes in the micrometer range (micro crystalline MC) in form of thin films have become important in many technologies due to their improved physical, chemical and mechanical properties. Usual the mechanical properties of such coatings are described by a Hardness value and a Young´s modulus measured by Instrumented Indentation Testing (IIT).The behavior of such coatings during indentation test is influenced by different size effects having their representative length scale – grain size, coating thickness, length that characterizes the depth dependence of the hardness (Indentation Size Effect ISE). To estimate realistic values for the intrinsic coating Hardness and Young´s modulus all size effects have to be considered. For this work thin nano crystalline Ni – coatings (average grain size 30 nm) with thickness from 1 μm to 5 μm were electrodeposited on brass substrates. Indentation test...
Durch faseroptische Sensoren konnen Bauteile im Einsatz kontinuierlich uberwacht und fruhzeitig I... more Durch faseroptische Sensoren konnen Bauteile im Einsatz kontinuierlich uberwacht und fruhzeitig Informationen uber Materialveranderungen gewonnen werden. Mittels einer magnetostriktiven Aktorschicht, welche den Sensor umhullt, kann nun auch die korrekte Sensorfunktion jederzeit kontrolliert werden. Als Aktorschicht eignet sich galvanisch abgeschiedenes reines Nickel oder Nickel-Eisen in der Zusammensetzung 50:50. Um diese haftfest mit dem Sensor zu verbinden wurde ein ECD/PVD-Kombinationsschichtsystem entwickelt. Die mechanischen Eigenschaften der ECD-Schicht konnen sowohl mit einer auf die Fasergeometrie angepassten instrumentierten Eindringprufung als auch einem 2-Punkt-Biegeversuch bestimmt werden.
Discussing the applicability of the standard ISO 14577 analysing examples from the daily experime... more Discussing the applicability of the standard ISO 14577 analysing examples from the daily experimental praxis of thin films testing it will be shown that the always used model proposed by Oliver and Pharr already in 1992 [1] describes the complex contact mechanics only approximately. Already more than 10 years ago Pharr suggested a straightforward method to separate the purely elastic indenter stress field from the residual stress left from plastic deformation [2]. Schwarzer combined his own extended solution of the Hertz problem [3] with the so called concept of effective indenter shape to an complex tool for evaluating experimental indentation data [e.g. 4,5]. Today this solution is available as the software packageO&PfC from SIO. Analysing examples from the daily experimental praxis using the O&PfCsofttware package the connection between the standard ISO 14577 and the concept of effective indenter shape indenter will be illustrated. It will be shown that only accurate experimental...
The utility of ion implantation to investigate the influence of reactive ions on the secondary io... more The utility of ion implantation to investigate the influence of reactive ions on the secondary ion emission has been demonstrated by COLLIGON and KIRIAKIDES [1] in the case of copper matrix material.
The chemical and microstructural changes occurring during braking simulation tests at the surface... more The chemical and microstructural changes occurring during braking simulation tests at the surface of a conventional brake pad material were investigated mainly by scanning and transmission electron microscopy and surface analytical techniques. It can be shown that patches of a third body material develop, comprising a compositional mix of all constituents of the pad and iron oxides from the disk.
The experimental investigations of the ion beam gettering of copper in GaP outlined in this paper... more The experimental investigations of the ion beam gettering of copper in GaP outlined in this paper indicate that (i) copper atoms decorate the ion implanted damage not only of noble gas atoms but also other atoms and especially damage region caused by copper ions themselves; (ii) in comparison with the gettering of process-induced midgap recombination centers in Si [9] and
The draft of part 5 of ISO 14577 specifies verification and calibration of testing machines for c... more The draft of part 5 of ISO 14577 specifies verification and calibration of testing machines for carrying out the measurement of the dynamic material response when an oscillatory force or displacement, with amplitudes small in comparison to the prescribed target values, is imparted to the indenter while the indenter is continuously loaded to a prescribed target load or target depth or while the load or displacement is held constant at a prescribed target value. In case of a material showing plastic-elastic behavior, the measured dynamic response is used for continuous evaluation of the dynamic stiffness of the contact as a function of depth and frequency. Using the dynamic stiffness of the contact a reduced dynamic modulus will be calculated. In case of a material showing visco-elastic behavior from the measured dynamic response also the dynamic contact damping coefficient as function of depth and frequency is evaluated continuously. Using dynamic contact stiffness and dynamic contact damping coefficient reduced lost and storage modulus for visco-elastic materials will be calculated. The main normative requirements of the draft are discussed and their applications are illustrated by examples from daily experimental praxis.
International Journal of Materials Research, Nov 1, 2005
An extensive comparison between the conventional Vickers hardness at 500 mN and indentation hardn... more An extensive comparison between the conventional Vickers hardness at 500 mN and indentation hardness measured with Vickers indenters at 500 mN is presented for up to 20 different materials and for three different instruments. Additionally, the indentation modulus is compared to Young’s modulus, which was measured with alternative methods or taken from the literature. It is shown that the agreement between the results from depth-sensing indentation and the reference values can be improved by additional corrections, for the calculation of the indentation area. With corrections the mean hardness difference to the Vickers hardness reference as average of all investigated materials can be reduced to about 10 % although disturbing pile-up or sink-in effects can still not be considered. For the modulus, the mean difference was only about 6 %.
Focal adhesion contact formation by fibroblasts cultured on surface-modified dental implants: an ... more Focal adhesion contact formation by fibroblasts cultured on surface-modified dental implants: an in vitro study Birte Größner-Schreiber
Do different implant surfaces exposed in the oral cavity of humans show different biofilm composi... more Do different implant surfaces exposed in the oral cavity of humans show different biofilm compositions and activities?
The ISO/DIS 14577 Metallic materials - Instrumented indentation test for hardness and materials p... more The ISO/DIS 14577 Metallic materials - Instrumented indentation test for hardness and materials parameters Part 1-3 (IIT) concerns test forces up to 30 kN. The paper reports on IIT at test forces ranging from 0.002 N to 1000 N on non magnetizable steel X8 CrMnN 18- 18 (1.386) with well polished surface using Vickers indenter and four hardness machines of different design (Nano Indenter XP, Fischerscope H 100, Zwick Z005 with Universal hardness head and a laboratory four-column set up materials testing machine) according to the standard. Using mostly identical test parameters the results of the different machines are almost in good agreement. Estimated small differences are caused by the different uncertainties of the used machines and by different methods of mathematical analysis of the detected raw data.
Polycrystalline Ni materials with grain sizes less than 100 nm (nano crystalline NC) and with gra... more Polycrystalline Ni materials with grain sizes less than 100 nm (nano crystalline NC) and with grain sizes in the micrometer range (micro crystalline MC) in form of thin films have become important in many technologies due to their improved physical, chemical and mechanical properties. Usual the mechanical properties of such coatings are described by a Hardness value and a Young´s modulus measured by Instrumented Indentation Testing (IIT).The behavior of such coatings during indentation test is influenced by different size effects having their representative length scale – grain size, coating thickness, length that characterizes the depth dependence of the hardness (Indentation Size Effect ISE). To estimate realistic values for the intrinsic coating Hardness and Young´s modulus all size effects have to be considered. For this work thin nano crystalline Ni – coatings (average grain size 30 nm) with thickness from 1 μm to 5 μm were electrodeposited on brass substrates. Indentation test...
Durch faseroptische Sensoren konnen Bauteile im Einsatz kontinuierlich uberwacht und fruhzeitig I... more Durch faseroptische Sensoren konnen Bauteile im Einsatz kontinuierlich uberwacht und fruhzeitig Informationen uber Materialveranderungen gewonnen werden. Mittels einer magnetostriktiven Aktorschicht, welche den Sensor umhullt, kann nun auch die korrekte Sensorfunktion jederzeit kontrolliert werden. Als Aktorschicht eignet sich galvanisch abgeschiedenes reines Nickel oder Nickel-Eisen in der Zusammensetzung 50:50. Um diese haftfest mit dem Sensor zu verbinden wurde ein ECD/PVD-Kombinationsschichtsystem entwickelt. Die mechanischen Eigenschaften der ECD-Schicht konnen sowohl mit einer auf die Fasergeometrie angepassten instrumentierten Eindringprufung als auch einem 2-Punkt-Biegeversuch bestimmt werden.
Discussing the applicability of the standard ISO 14577 analysing examples from the daily experime... more Discussing the applicability of the standard ISO 14577 analysing examples from the daily experimental praxis of thin films testing it will be shown that the always used model proposed by Oliver and Pharr already in 1992 [1] describes the complex contact mechanics only approximately. Already more than 10 years ago Pharr suggested a straightforward method to separate the purely elastic indenter stress field from the residual stress left from plastic deformation [2]. Schwarzer combined his own extended solution of the Hertz problem [3] with the so called concept of effective indenter shape to an complex tool for evaluating experimental indentation data [e.g. 4,5]. Today this solution is available as the software packageO&PfC from SIO. Analysing examples from the daily experimental praxis using the O&PfCsofttware package the connection between the standard ISO 14577 and the concept of effective indenter shape indenter will be illustrated. It will be shown that only accurate experimental...
The utility of ion implantation to investigate the influence of reactive ions on the secondary io... more The utility of ion implantation to investigate the influence of reactive ions on the secondary ion emission has been demonstrated by COLLIGON and KIRIAKIDES [1] in the case of copper matrix material.
The chemical and microstructural changes occurring during braking simulation tests at the surface... more The chemical and microstructural changes occurring during braking simulation tests at the surface of a conventional brake pad material were investigated mainly by scanning and transmission electron microscopy and surface analytical techniques. It can be shown that patches of a third body material develop, comprising a compositional mix of all constituents of the pad and iron oxides from the disk.
The experimental investigations of the ion beam gettering of copper in GaP outlined in this paper... more The experimental investigations of the ion beam gettering of copper in GaP outlined in this paper indicate that (i) copper atoms decorate the ion implanted damage not only of noble gas atoms but also other atoms and especially damage region caused by copper ions themselves; (ii) in comparison with the gettering of process-induced midgap recombination centers in Si [9] and
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