Thin Films: Stress Measurement Techniques

In recent years, as a result of increasing environmental concerns, biodegradable materials have gained great attention. With the rapid development of electronic technology, the importance of innovation and development of low-cost, sustainable, transient bioelectronics materials is increasing. In this research, the preparation of Poly(Vinyl Alcohol) (PVA), Chitosan (CS), and Multi-Walled Carbon nanotube (MWCNT) biocomposite films have been described. The solution mixing, ultrasonic mixing, and spin coating techniques were used to prepare the PVA/CS/MWCNT biocomposite thin films. UV–Vis absorption spectroscopy and two-point probe resistivity measurement techniques were used to study the optical and electrical properties of the biocomposite thin films. Optical band gap energies ( Eg) of PVA/CS/MWCNT biocomposites were obtained using the Tauc and Absorbance Spectrum Fitting (ASF) methods. Results obtained with both methods were found to be exactly the same. Experimental results have shown that with increasing MWCNT concentration, electrical conductivity (σ) increases from 1.75x10−16 S to 2.94x10−3 S, and Eg decreases significantly. At the same time, the fundamental optical parameters such as band tail (Urbach) energy ( Eu), refractive index ( n), absorption ( α), and extinction ( k) coefficient of the PVA/CS/MWCNT biocomposites were investigated in the UV-VIS range. The improvement observed in the optical and electrical properties of PVA/CS/MWCNT biocomposite films shows that these composites could be used as bioelectronics materials.

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Sputtered WSix for micromechanical structures

Journal of Materials Research ◽

10.1557/jmr.1995.1710 ◽

1995 ◽

Vol 10 (7) ◽

pp. 1710-1720 ◽

Cited By ~ 7

Author(s):

Muh-Ling Ger ◽

Richard B. Brown

Keyword(s):

Thin Films ◽

Integrated Circuit ◽

Elastic Moduli ◽

Stress Measurement ◽

Rutherford Backscattering Spectrometry ◽

Thermal Coefficient ◽

Deposition Pressure ◽

Sputtered Films ◽

Effect Transistor ◽

Micromechanical Structures

Tungsten silicide (WSix) thin tilms have been investigated for use as integrated circuit interconnect and self-aligned MESFET (metal-semiconductor field-effect transistor) gates because of their low resistivity and thermal and chemical stability. These same characteristics make them interesting materials for prospective use in micromechanical structures. However, little information on residual stresses, elastic moduli, or other micromechanical properties has been available for refractory metal silicide thin films. This paper presents the morphology and stress characteristics of cosputtered WSix thin films, including crystal structure variations and orientation-dependent stresses, as a function of the deposition pressure. The compositions of WSix thin films were analyzed by Rutherford backscattering spectrometry (RBS). The biaxial elastic modulus and thermal coefficient of expansion were found for the sputtered films. Stress-measurement methods and annealing are discussed. Released diaphragms of different sizes and shapes, having controlled residual stress, have been fabricated.

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DIC Image on FIB Ring-Core Analysis of Depth Sensing Residual Stress Measurement of Thin Films

Conference Proceedings of the Society for Experimental Mechanics Series - Advancement of Optical Methods & Digital Image Correlation in Experimental Mechanics, Volume 3 ◽

10.1007/978-3-319-97481-1_15 ◽

2018 ◽

pp. 109-111 ◽

Cited By ~ 1

Author(s):

Wen Chieh Pan ◽

Ang-Ting Tsai ◽

Fa-Yen Cheng ◽

Terry Yuan-Fang Chen ◽

Ming-Tzer Lin

Keyword(s):

Thin Films ◽

Residual Stress ◽

Stress Measurement ◽

Residual Stress Measurement ◽

Core Analysis ◽

Depth Sensing ◽

Ring Core

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Residual stress measurement techniques for Ti6Al4V parts fabricated using selective laser melting: state of the art review

Rapid Prototyping Journal ◽

10.1108/rpj-04-2019-0097 ◽

2020 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Ruben B.O. Acevedo ◽

Klaudia Kantarowska ◽

Edson Costa Santos ◽

Marcio C. Fredel

Keyword(s):

Residual Stress ◽

Selective Laser Melting ◽

Stress Measurement ◽

State Of The Art ◽

Measurement Techniques ◽

Residual Stress Measurement ◽

Hole Drilling ◽

X Ray Diffraction ◽

Laser Melting ◽

Content Type

Purpose This paper aims to generate a review of available techniques to measure Residual Stress (RS) in Ti6Al4V components made by Ti6Al4V. Design/methodology/approach State of the art; literature review in the field of Residual Stress measurement of Ti6Al4V parts made by selective laser melting (SLM). Findings Different Residual Stress measurement techniques were detailed, regarding its concept, advantages and limitations. Regarding all researched references, hole drilling (semi destructive) and X-ray diffraction (nondestructive) were the most cited techniques for Residual Stress measurement of Ti6Al4V parts made by SLM. Originality/value An extensive analysis of RS measurement techniques for Ti6Al4V parts made by SLM.

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Measurement of Residual Stresses within a PWR Swaged Heater Tube

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.70.279 ◽

2011 ◽

Vol 70 ◽

pp. 279-284 ◽

Cited By ~ 2

Author(s):

D.M. Goudar ◽

Ed J. Kingston ◽

Mike C. Smith ◽

Sayeed Hossain

Keyword(s):

Residual Stress ◽

Stress Distribution ◽

Stress Measurement ◽

Measurement Techniques ◽

Residual Stress Distribution ◽

Hole Drilling ◽

Shear Stresses ◽

Outer Diameter ◽

Near Surface ◽

Heater Tube

Frequent failures of the pressuriser heater tubes used in Pressurised Water Reactors (PWRs) have been found. Axial cracks initiating from the tube outer diameter have been detected in some tubes as well as the resulting electrical problems. Replacement of the heater tubes requires an undesirably prolonged plant shutdown. In order to better understand these failures a series of residual stress measurements were carried out to obtain the near surface and through-thickness residual stress profiles in a stainless steel pressuriser heater tube. Three different residual stress measurement techniques were employed namely, Deep-Hole Drilling (DHD), Incremental Centre Hole Drilling (ICHD) and Sachs’ Boring (SB) to measure the through thickness residual stress distribution in the heater tubes. Results showed that the hoop stresses measured using all three techniques were predominantly tensile at all locations, while the axial stresses were found to be tensile at the surface and both tensile and compressive as they reduce to small magnitudes within the tube. The magnitude of the in-plane shear stresses was small at all measurement depths at all locations. The various measurement methods were found to complement each other well. All the measurements revealed a characteristic profile for the through-thickness residual stress distribution.

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Effect of Gauge Volume on the Residual Stress Measurement Using Deep Hole Drilling Technique

ASME 2010 Pressure Vessels and Piping Conference: Volume 6, Parts A and B ◽

10.1115/pvp2010-25460 ◽

2010 ◽

Cited By ~ 1

Author(s):

Amir H. Mahmoudi ◽

David J. Smith ◽

Chris E. Truman ◽

Martyn J. Pavier

Keyword(s):

Residual Stress ◽

Material Removal ◽

Stress Measurement ◽

Measurement Techniques ◽

Residual Stress Measurement ◽

Hole Drilling ◽

Deep Hole ◽

Deep Hole Drilling ◽

Gauge Volume ◽

Drilling Technique

Accurate evaluation of residual stress is essential if is to be taken into account in structural integrity assessments. For thick components, many non-destructive residual stress measurement techniques cannot be used since they are unable to measure the stresses deep within the component. Measurement techniques which involve mechanical strain relief through material removal are the only alternative. Recently, it has been found that these techniques may fail to measure the stresses correctly when highly triaxial stresses are present because plastic redistribution can occur when the material removal is carried out. The Deep Hole Drilling technique is a very powerful method to measure the stresses within very thick engineering components. However, it can suffer from high levels of plasticity and lead to inaccurate results. It is shown in the present research that the effect of plasticity on the measured stresses can be eliminated. In the present work, the effect of gauge volume on the plasticity effect is investigated.

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