The relationship between indentation and uniaxial creep in amorphous selenium

Poisl, W. Howard; Oliver, W. C.; Fabes, B. D.

doi:10.1557/jmr.1995.2024

Cited by 181 publications

(94 citation statements)

References 41 publications

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“…7,12 The most common experiments are constant-load indentation creep tests at room temperature (RT), where the maximum load is held constant for a preset time between 1 min and 1 h, while the indentation depth is monitored as a function of time. [13][14][15][16] The apparent change in displacement is used to evaluate the time-dependent deformation behavior. However, thermal drift influences are found to be strongly affecting the displacement measurements, explaining the huge variations within the data previously reported in literature.…”

Section: Introductionmentioning

confidence: 99%

An improved long-term nanoindentation creep testing approach for studying the local deformation processes in nanocrystalline metals at room and elevated temperatures

et al. 2013

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The strain-rate sensitivity of ultrafine-grained aluminum (Al) and nanocrystalline nickel (Ni) is studied with an improved nanoindentation creep method. Using the dynamic contact stiffness thermal drift influences can be minimized and reliable creep data can be obtained from nanoindentation creep experiments even at enhanced temperatures and up to 10 h. For face-centered cubic (fcc) metals it was found that the creep behavior is strongly influenced by the microstructure, as nanocrystalline (nc) as well as ultrafine-grained (ufg) samples show lower stress exponents when compared with their coarse-grained (cg) counterparts. The indentation creep behavior resembles a power-law behavior with stress exponents n being ; 20 at room temperature. For higher temperatures the stress exponents of ufg-Al and nc-Ni decrease down to n ; 5. These locally determined stress exponents are similar to the macroscopic exponents, indicating that similar deformation mechanisms are acting during indentation and macroscopic deformation. Grain boundary sliding found around the residual indentations is related to the motion of unconstrained surface grains.

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Section: Introductionmentioning

confidence: 99%

An improved long-term nanoindentation creep testing approach for studying the local deformation processes in nanocrystalline metals at room and elevated temperatures

et al. 2013

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“…22 For creep-dominant materials, a nanoindenter can be used to quantitatively measure the creep parameters. When traditional creep parameters are calculated based on creep experiments of the uniaxial tensile stress state, the steady-state indentation strain rate is often described as the following [23][24][25][26][27][28] :…”

Section: Nanoindentationmentioning

confidence: 99%

Nanoindentation investigation of the stress exponent for the creep of dung beetle (Copris ochusMotschulsky) cuticle

Zhang

Sun

et al. 2016

Bioengineered

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ABSTACTWith the rapid development of bionic science, especially the progress that has been made in the fields of biomaterials and biomimetics, there is now great interest in the surface and internal mechanical properties of biological materials at the micro-and nanoscale. The study of micro-and nanoscale biomaterial mechanical properties could enable interdisciplinary applications in materials science, biological science and bionic science. Dung beetle (Copris ochus Motschulsky) cuticle is a viscoelastic material that is both viscous and flexible via elastic deformation under external forces; where stress s, strain e and elastic modulus E are related in the following way: s D Ee. In addition, as s is related to the rate of strain, time is also a factor. The stress-strain relationships of various parts of dung beetle cuticle were investigated in this paper. As time increased, the stress and strain of the material were found to decrease and increase, respectively, indicating that when the material was indented for a certain period, the interaction force between the indenter and the material gradually achieved a state of dynamic equilibrium. However, strain continued to occur until reaching a point of equilibrium because of the creep phenomenon. The stress-strain curves showed a strong character in each holding time condition: the longer the holding time, the more flattened the stress-strain curve. These findings will be useful in the advanced design of strong, lightweight, and biomimetic composites.

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“…It can reveal a wealth of detailed information about the mechanisms and mechanics of the studied thin film materials, including elastic modulus, hardness, surface adhesion, creep, and stress relaxation behaviors, etc (Tymiak et al 2001;Bei et al 2004;Pharr 1992, 2004;Lucas and Oliver 1999;Poisl et al 1995;Elmustafa and Stone 2003;Nieh 2003, 2004;Li and Ngan 2004).…”

Section: Nanoindentation Testsmentioning

confidence: 99%

“…In this project, two types of nanoindentation experiments, constant rate of loading (CRL) and indentation load relaxation (ILR) (Poisl 1995), will be conducted on the blank PECVD SiO, films. Both the time-independent and the time-dependent plastic responses are studied.…”

Section: Nanoindentation Testsmentioning

confidence: 99%

“…hand h, are the measured depth (also the instant maximum depth) and the contact depth, respectively. In this case, the indentation strain rate at any stage is defined as (Poisl et al 1995;Tabor 1951): For conical and pyramidal (such as Berkovich) tips, the indentation strain rate for deep indents is usually expressed as (Poisl et al 1995;Hill 1992;Bower et al 1993;Storfkers and Larsson 1994):…”

Section: Nanoindentation Testsmentioning

confidence: 99%

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Residual Stress and Fracture of PECVD Thick Oxide Films for Power MEMS Structures and Devices

Zhang¹

2007

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, seerching data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Washington Headquarters Service, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and SUPPLEMENTARY NOTES14. ABSTRACT Plasma enhanced chemical vapor deposited (PECVD) silicon oxide (SiOx) is the most commonly used interlayer dielectric (ILD) in MEMS devices and structures. In this project, PECVD SiOx is chosen as an example for the systematic study of mechanical behavior and underlying casual mechanisms of amorphous thin films for MEMS applications, which are generally less well understood because of the complex interplay among the deformation mechanisms. In this project, PECVD SiO, is chosen as an example for the systematic study of mechanical behavior and underlying causal mechanisms of amorphous thin films for MEMS applications, which are generally less well understood because of the complex interplay among the deformation mechanisms. SUBJECT TERMSMechanical behaviors of the PECVD SiOx thin films are probed at 1) different size scales (from wafer level down to micro/nano-scale, and different lengthscale within each realm); 2) different temperatures (from room temperature up to 1100 0C); and 3) with a combination of different experimental techniques (such as substrate curvature measurements, nanoindentation tests, and a novel "microbridge testing" technique, etc.). A broad range of mechanical analysis is covered, including film stress and related material properties changes, elastic properties, plastic properties (both time-independent and time-dependent), deformation mechanisms (both at room temperature and elevated temperatures).Wherever applicable, materials analysis techniques such as SEM, AFM, FTIR, XRD, and SIMS were employed to strengthen the discussions on the structureproperties relationship and the causal mechanisms of the mechanical responses of the PECVD SiOx. These experiments reveal various interesting arid disiirictive characteristics of the mechanical responses of the PECVD SiOx thin films, and the microstructural causal mechanisms for each of them are analyzed in depth.The outcome of this work will provide a comprehensive characterization of the mechanical responses of the PECVD SiOx thin films under different thermal conditions, stress levels, size scales, and in both elastic and plastic regions. In addition, both new experimental methodologies and theoretical models for data 3 analysis are resulted, which can be readily applied to a wide variety of thin film materials for various different applications. Last but not least, the physical causal mechanisms for the experimental results are elucidated, ...

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The relationship between indentation and uniaxial creep in amorphous selenium

Cited by 181 publications

References 41 publications

An improved long-term nanoindentation creep testing approach for studying the local deformation processes in nanocrystalline metals at room and elevated temperatures

An improved long-term nanoindentation creep testing approach for studying the local deformation processes in nanocrystalline metals at room and elevated temperatures

Nanoindentation investigation of the stress exponent for the creep of dung beetle (Copris ochusMotschulsky) cuticle

Residual Stress and Fracture of PECVD Thick Oxide Films for Power MEMS Structures and Devices

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