Elastic Properties of Artificially Layered Thin Films

1987 ◽  
Vol 103 ◽  
Author(s):  
Robert C. Cammarata

ABSTRACTEnhancements in the elastic moduli by factors of two or more in compositionally modulated metallic thin films have been observed for a certain range of composition modulation wavelengths. The experimental and theoretical understanding of this phenomenon, known as the supermodulus effect, is reviewed. Also, the mechanical properties of other artificially layered and composite materials are discussed and compared with the behavior of metallic superlattice thin films.

1993 ◽  
Vol 8 (11) ◽  
pp. 2908-2915 ◽  
Author(s):  
M.J. Loboda ◽  
M.K. Ferber

Amorphous hydrogenated silicon carbide (a–SiC: H) thin films (t < 1 μm) were grown from two different precursor gases, a methane/silane mixture and silacyclobutane (SiC3H8). Plasma enhanced chemical vapor deposition was used to deposit a–SiC: H thin films on silicon substrates at temperatures of 175 °C and 600 °C. These a–SiC: H films were characterized using the mechanical properties microprobe (nanoindenter) and by scratch testing. Data and mechanical properties information collected from these measurements have been correlated with film process conditions and materials characteristics. A simplified approach was used to calculate the average nanoindentation hardness from shallow indentations. Using this technique, results for a silicon wafer are in good agreement with that previously reported. Analysis of the substrate influence on the thin film nanoindentation data implies that the measured hardness is relatively unaffected by the substrate, while the measured elastic properties are somewhat influenced by the substrate. The a–SiC: H film hardness is shown to depend on the precursor gas and molecular bonding, while the elastic properties vary with precursor gas, composition, and density, as influenced by the plasma source deposition power. The MPM data and scratch test data show similar correlations to plasma source power, film structure, and film composition.


2010 ◽  
Vol 20 (6) ◽  
pp. 983-991 ◽  
Author(s):  
Eva Pellicer ◽  
Aïda Varea ◽  
Salvador Pané ◽  
Bradley J. Nelson ◽  
Enric Menéndez ◽  
...  

2020 ◽  
Author(s):  
Taylor C. Stimpson ◽  
Daniel A. Osorio ◽  
Emily D. Cranston ◽  
Jose Moran-Mirabal

<p>To engineer tunable thin film materials, accurate measurement of their mechanical properties is crucial. However, characterizing the elastic modulus with current methods is particularly challenging for sub-micrometer thick films and hygroscopic materials because they are highly sensitive to environmental conditions and most methods require free-standing films which are difficult to prepare. In this work, we directly compared three buckling-based methods to determine the elastic moduli of supported thin films: 1) biaxial thermal shrinking, 2) uniaxial thermal shrinking, and 3) the mechanically compressed, strain-induced elastic buckling instability for mechanical measurements (SIEBIMM) method. Nanobiocomposite model films composed of cellulose nanocrystals (CNCs) and polyethyleneimine (PEI) were assembled using layer-by-layer deposition to control composition and thickness. The three buckling-based methods yielded the same trends and comparable values for the elastic moduli of each CNC-PEI film composition (ranging from 15 – 44 GPa, depending on film composition). This suggests that the methods are similarly effective for the quantification of thin film mechanical properties. Increasing the CNC content in the films statistically increased the modulus, however, increasing the PEI content did not lead to significant changes. The standard deviation of elastic moduli determined from SIEBIMM was 2-4 times larger than for thermal shrinking, likely due to extensive cracking and partial film delamination. In light of these results, biaxial thermal shrinking is recommended as the method of choice because it affords the simplest implementation and analysis and is the least sensitive to small deviations in the input parameter values, such as film thickness or substrate modulus.</p>


2002 ◽  
Vol 741 ◽  
Author(s):  
H.D. Espinosa ◽  
B. Peng ◽  
K.-H. Kim ◽  
B.C. Prorok ◽  
N. Moldovan ◽  
...  

ABSTRACTMicrocantilever deflection and the membrane deflection experiment (MDE) were used to examine the elastic and fracture properties of ultrananocrystalline diamond (UNCD) thin films in relation to their application to microelectromechanical systems (MEMS). Freestanding microcantilevers and membranes were fabricated using standard MEMS fabrication techniques adapted to our UNCD film technology. Elastic moduli measured by both methods described above are in agreement, with the values being in the range 930 and 970 GPa with both techniques showing good reproducibility. The MDE test showed fracture strength to vary from 3.95 to 5.03 GPa when seeding was performed with ultrasonic agitation of nanosized particles.


2016 ◽  
Vol 89 (3) ◽  
Author(s):  
Duong Dai Phuong ◽  
Nguyen Thi Hoa ◽  
Vu Van Hung ◽  
Doan Quoc Khoa ◽  
Ho Khac Hieu

2011 ◽  
Vol 38 (3) ◽  
pp. 209-297 ◽  
Author(s):  
Ekaterina Novitskaya ◽  
Po-Yu Chen ◽  
Elham Hamed ◽  
Li Jun ◽  
Vlado Lubarda ◽  
...  

In this review, recent advances on the measurement and modeling of elastic properties of cortical and trabecular bone are presented. Bone is a multifunctional material which among its other functions serves as a support for other tissues in the body. As a structural material it is stiff, strong, tough, lightweight and is adaptable. Its excellent mechanical properties are due to its complex, composite and hierarchical structure. In this paper, we outline the experimental approaches that have been used to characterize bone?s structure, composition and elastic properties at several different length scales. Then, we discuss different modeling approaches that have been employed to compute bone?s elastic moduli. We conclude by discussing the challenges and open issues in this area. Analysis of bone is of importance in orthopedics. Also, gained knowledge on bone can be used by engineers to design new bioinspired composite materials for a wide range of engineering applications.


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