A Membrane Deflection Fracture Experiment to Investigate Fracture Toughness of Freestanding MEMS Materials

2003 ◽  
Vol 795 ◽  
Author(s):  
H. D. Espinosa ◽  
B. Peng

ABSTRACTThis paper presents a novel Membrane Deflection Fracture Experiment (MDFE) to investigate the fracture toughness of MEMS and other advanced materials in thin film form. It involves the stretching of freestanding thin-film membranes, in a fixed-fixed configuration, containing pre-existing cracks. The fracture behavior of ultrananocrystalline diamond (UNCD), a material developed at Argonne National Laboratory, is investigated to illustrate the methodology. When the fracture initiates from sharp cracks, produced by indentation, the fracture toughness was found to be 4.7 MPa m1/2. When the fracture initiates from blunt notches with radii about 100 nm, machined by focused ion beam (FIB), the mean value of the apparent fracture toughness was found to be 7.2 MPa m1/2. Comparison of these two values, using the model proposed by Drory et al. [9], provides a correction factor of 2/3, which corresponds to a mean value of ρ/2x=1/2.

Author(s):  
Mohan Prasad Manoharan ◽  
Amit Desai ◽  
Amanul Haque

Thin film specimens of titanium - titanium nitride multilayer erosion resistant coating were prepared using liftout technique in Focused Ion Beam - Scanning Electron Microscope (SEM). The fracture toughness of the thin film specimen was measured in situ using a cantilever bending experiment in SEM to be 11.33 MPa/m0.5, twice as much as conventional TiN coatings. Ti–TiN multi-layer coatings are part of a new class of advanced erosion resistant coatings and this paper discusses an experimental technique to measure the fracture toughness of these coatings.


2015 ◽  
Vol 771 ◽  
pp. 108-111
Author(s):  
Harini Sosiati ◽  
Satoshi Hata ◽  
Toshiya Doi

A focused ion beam (FIB) mill equipped with a microsampling (MS) unit and combined with transmission electron microscopy (TEM)/scanning TEM-energy dispersive x-ray spectroscopy (STEM-EDXS) is a powerful tool for studies of the functional advanced materials. For the studies, the specimen must be prepared as a thin foil which is tranparent to the electron beam. Focused ion beam is very effective method for fabricating TEM specimen of the cross-sectional thin film with the “lift-out” technique using a tungsten (W)-needle probe as a micromanipulator. A multilayer film of MgB2/Ni deposited on a Si (001) substrate prepared by FIB-MS technique is presented. Before FIB fabrication, the surface of the multilayer film was coated with W-film to prevent the surface from bombardment by the ion beam. A bright field (BF)-STEM image of the multilayer film related to two-dimensional (2D) elemental mapping clearly showed the presence of MgB2-and Ni-nanolayers. The measured experimental spacing between Ni-nanolayers was comparable with the actual specimen design, but the thickness of Ni-nanolayer was not. Unexpected nanostructures of the formation of SiO2 film on the substrate surface and holes within the film were observed.


2019 ◽  
Vol 827 ◽  
pp. 196-202
Author(s):  
Hector A. Tinoco ◽  
Pavel Hutař ◽  
Benoit Merle ◽  
Mathias Göken ◽  
Tomáš Kruml

This paper presents a finite element analysis of a pre-cracked freestanding gold thin film subjected to bulge test. These tests were conducted in order to determine the elasto-plastic properties and fracture toughness of the gold films. For the experimental tests, a pre-crack was introduced in the center of the film by focused ion beam (FIB) milling with a length of 10 and a width of 100nm. For the numerical fracture analysis, the problem was divided into two stages; the first stage was the development of the numerical model on the whole film without pre-crack (elasto-plastic analysis) and the second one was performed on a film portion that included the pre-crack (sub-modeling stage). Three different notches (rounded, sharp and V-sharp) were applied to calculate the stress intensity factor around the crack tip using path independent J-integral. The obtained results show that the load-deflection curves for non-cracked and pre-cracked film reproduced the experiments using the calculated elasto-plastic properties. This indicates that the proposed models presented a good correlation and robustness. Additionally, fracture toughness values were calculated between 0.288 and 0.303with J-integral values 1.037 J/m2 (elastic) and 1.136 J/m2 (elasto-plastic) which correspond with other calculations available in the literature.


1999 ◽  
Vol 594 ◽  
Author(s):  
Ting Y. Tsui ◽  
Young-Chang Joo

AbstractA new experimental technique is developed to measure the fracture toughness of a hard metal thin film deposited on a soft substrate. A pre-crack was fabricated in the thin film by using the advanced focused ion beam (FIB) milling techniques. The crack extension force was generated by means of the indentation sinking-in effect. The effect creates a bending moment and tensile stress on the hard thin film near the indentation, which promotes crack growth. The amount of crack tip blunting prior to the critical failure was measured from the FIB cross-sectioned micrographs. By using the crack tip opening displacement model (CTOD), the fracture toughness of the thin film was calculated. The results show the nickel phosphorus (NiP) thin film fracture toughness is at least 15.0MPa√m. The finite element method (FEM) was used to understand the modes of mixity near the crack tip. The results indicate the crack tip modes of mixity are dominated by the Mode I opening, provided the indentation is sufficiently far from the pre-crack or the indentation depths is small when compared with the film thickness.


Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.


1990 ◽  
pp. 987-990
Author(s):  
M. Tanioku ◽  
K. Kuroda ◽  
K. Kojima ◽  
K. Hamanaka ◽  
Y. H. Hisaoka ◽  
...  
Keyword(s):  

MRS Advances ◽  
2017 ◽  
Vol 2 (26) ◽  
pp. 1405-1410
Author(s):  
Nobuhiro Matsuzaki ◽  
Ken-ichi Ikeda ◽  
Seiji Miura ◽  
Nobuaki Sekido ◽  
Takahito Ohmura

ABSTRACTAl3Nb is known as a high oxidation resistant material, while it is quite brittle. As the fracture toughness of Al3Nb single crystal and its dependence on the composition are not obtained, the micro-sized fracture testing proposed by Suzuki et al. was performed. Al3Nb single crystal micron-order size cantilevers with a chevron-notch were fabricated in a grain of two-phase polycrystalline alloys by using FIB (Focused Ion Beam). From the load-displacement curves during the bending by a nanoindenter, the average value of fracture toughness of Nb-rich Al3Nb is evaluated to be 2.90 MPam1/2, while the fracture toughness of Al-rich Al3Nb is also evaluated to be 2.82 MPam1/2. From this result, the fracture toughness of Al3Nb is less dependent on its Al/Nb ratio. Furthermore the fracture toughness of Al3 (Nb, V) was evaluated to be 2.82 MPam1/2.The fracture toughness of Al3Nb is seemingly insensitive to V addition.


1992 ◽  
Vol 279 ◽  
Author(s):  
A. T. Motta ◽  
L. M. Howe ◽  
P. R. Okamoto

ABSTRACTThin foils of Zircaloy-4 were irradiated with 350 KeV 40Ar ions in the dual ion beam/HVEM facility at Argonne National Laboratory at 300 – 650 K. The irradiation-induced araorphization of the intermetallic precipitates Zr (Cr, Fe)2 and Zr2 (Ni, Fe) was studied in situ. For Zr (Cr,Fe)2 precipitates the dose-to-amorphization was found to increase exponentially with temperature, with a critical temperature of about 650 K. The amorphization morphology was shown to be homogeneous, with no preferential site for nucleation, in contrast to neutron-irradiation amorphization which started at the precipitate-matrix interface. For Zr2 (Ni,Fe) precipitates it was found that amorphization occurred at 550 K and 600 K, whereas in neutron irradiation no amorphization has been observed at those temperatures. The results are discussed in the context of the previous experimental results of neutron and electron irradiation and likely amorphization mechanisms are proposed.


Author(s):  
Koji Miyazaki ◽  
Hiroshi Tsukamoto ◽  
Takahiro Miike ◽  
Toshiaki Takamiya

We fabricate metal thin film thermocouples (TFTCs). Au-Pt, Cu-Ni, and W-Ni are deposited on a glass plate using standard thin film processes. The dimension of thermocouple junction is 300μm × 300μm. The thermoelectric powers of TFTCs are different from those of bulk because diffusion of electrons is restricted by the very thin film. The film thickness of TFTCs is of the same order as the mean free path of electrons. However TFTCs are still useful for temperature measurements because the thermoelectric voltage is proportional to measured temperature at thermocouple junction. The response time of Au-Pt TFTCs is about 30ns when the surface of the glass is heated by a YAG pulsed laser. The result compares favorably with measurements by a thermoreflectance method. We also describe W-Ni nano-TFTCs fabricated by Focused Ion Beam for the measurement of temperature distribution in a sub-micron area. In order to reduce the size of the TFTCs we employ a 3-dimensional structure.


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