Influence of the Film Thickness on Texture, Residual Stresses and Cracking Behavior of PVD Tungsten Coatings Deposited on a Ductile Substrate

2008 ◽  
pp. 96-96-13 ◽  
Author(s):  
T Ganne ◽  
G Farges ◽  
J Crépin ◽  
R-M Pradeilles-Duval ◽  
A Zaoui
Keyword(s):  
Residual Stresses ◽  
Film Thickness ◽  
Cracking Behavior ◽  
Ductile Substrate

The Improvement of the Micro Torsional Mirror by a Reinforced Folded Frame

2000 ◽  
Author(s):  
Hung-Yi Lin ◽  
Weileun Fang
Keyword(s):  
Thin Film ◽  
Residual Stresses ◽  
Film Thickness ◽  
Experimental Results ◽  
Dynamic Loads ◽  
Inertia Force ◽  
Optical Performance ◽  
Thin Film Thickness ◽  
Static Loads ◽  
Dynamic Inertia

Abstract Stiffness of micromachined structures is limited by thin film thickness. Hence, static loads such as thin film residual stresses, or dynamic loads such as the inertia force could significantly deform the thinness micromachined torsional mirror. This work aims to stiffen the thin film micromachinined torsional mirror. The proposed torsional mirror exploits a reinforced frame to improve the stiffness of the mirror plate. Consequently, the mirror plate has less deformation no matter subject to the residual stresses or to the dynamic inertia force. In addition the reinforced frame stiffen the mirror without increasing the mass significantly. In application of this technique, the micro torsional mirror was fabricated through the integration of DRIE, conventional bulk and surface micromachining processes. The experimental results demonstrated that the proposed design significantly improves the flatness of the mirror plate in both static and dynamic conditions. Consequently, the optical performance of the micro torsional mirror was improved.

RESIDUAL STRESSES IN OBLIQUE INCIDENCE DEPOSITED ALUMINA THIN FILM

2014 ◽  
Vol 21 (02) ◽  
pp. 1450024 ◽  
Author(s):  
LIJUN HE ◽  
CHUAN LI ◽  
XINGZHAO LIU
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Residual Stresses ◽  
Film Thickness ◽  
Substrate Temperature ◽  
Deposition Rate ◽  
Growth Parameters ◽  
Testing Temperature ◽  
Alumina Thin Film ◽  
Inclined Angle

Residual stresses of alumina thin film deposited on silicon substrate by using electron beam evaporation with oblique angle deposition (OAD) method are studied. The growth parameters that affect the residual stresses of alumina thin film, such as the substrate temperature, the deposition rate, the film thickness, the inclined angle, and the testing temperature are discussed. The results show that the tensile stress value decreases with the increasing substrate temperature, and the compressive stress value increases with the increasing substrate temperature at various inclined angles. Along with the deposition rate increasing, the residual stress value decreases at various inclined angles. With the increasing film thickness, the residual stress value decreases at various inclined angles. With the increasing testing temperature, the residual stress value increases at various inclined angles. While the alumina thin film residual stress value is small at high inclined angle. By choosing the appropriate film preparation parameters, the alumina thin film residual stress is effectively controlled.

scholarly journals Prediction of Reheat Cracking Behavior in a Service Exposed 316H Steam Header

2020 ◽  
pp. 2050009
Author(s):  
Haoliang Zhou ◽  
Ali Mehmanparast ◽  
Kamran Nikbin
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Early Stage ◽  
Creep Crack Growth ◽  
Cracking Behavior ◽  
Displacement Boundary ◽  
Root Cause ◽  
Reheat Cracking ◽  
Weld Toe ◽  
Steam Header

Reheat cracking in an ex-service Type 316H stainless steel steam header component has been investigated in this study. The examined steam header was in service for 87,790[Formula: see text]h and the cracks in this component were found in the vicinity of the weld toe. The root cause of this type of failure was due to the welding residual stresses. The welding-induced residual stresses had been present in the header at the early stage of the operation and were released during service. In this paper, a novel technique has been proposed to simulate the residual stress distribution normal to the crack direction by applying remote fixed displacement boundary conditions in an axisymmetric model. This approach can simulate the presence of residual stresses in actual components without the need to develop full weld simulation to quantify them. The predicted residual stress levels and distributions normal to the crack direction have been found in good agreement with the measured residual stresses available in the literature for a similar header. The creep crack growth (CCG) rates have been characterized using the fracture mechanics [Formula: see text] parameter and estimated using predictive models.

Uncertainty Sampling of Weld Residual Stress Fields in Probabilistic Analysis: Part II — Examples

2016 ◽  
Author(s):  
Robert E. Kurth ◽  
Cédric J. Sallaberry ◽  
Frederick W. Brust ◽  
Elizabeth A. Kurth ◽  
Michael L. Benson ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Residual Stresses ◽  
Assessment Tool ◽  
Lessons Learned ◽  
Piping System ◽  
Primary System ◽  
Cracking Behavior ◽  
System Pressure ◽  
Piping Systems ◽  
Low Probability

NRC Standard Review Plan (SRP) 3.6.3 describes Leak-Before-Break (LBB) assessment procedures that can be used to assess compliance with the 10CFR50 Appendix A, GDC-4 requirement that primary system pressure piping exhibit an extremely low probability of rupture. SRP 3.6.3 does not allow for assessment of piping systems with active degradation mechanisms, such as Primary Water Stress Corrosion Cracking (PWSCC) which is currently occurring in systems that have been granted LBB approvals. US NRC staff, working cooperatively with the Electric Power Research Institute through a memorandum of understanding, conducted a multi-year project that focused on the development of a viable method and approach to address the effects of PWSCC in primary piping systems approved for LBB. This project, called eXtremely Low Probability of Rupture (xLPR) [1], defined the requirements necessary for a modular-based probabilistic fracture mechanics assessment tool to directly assess compliance with the regulations. Using the lessons learned from the pilot study, the production version of this code, designated as Version 2.0, focused on those primary piping systems previously approved for LBB. In this version the appropriate fracture mechanics-based models are employed to model the physical cracking behavior and a variety of computational options are provided to characterize, categorize and propagate problem uncertainties. One of the most influential uncertainty on risk in the xLPR code is the one associated with weld residual stresses (WRS). WRS plays a key role in both crack initiation and crack growth. PWSCC is mainly driven by tensile stresses, whose major contributors are the tensile weld residual stresses that develop during fabrication of the piping system. Handling the uncertainty involved with WRS within a probabilistic framework is quite challenging. A companion paper presents the selected approach to represent uncertainty within the framework of the xLPR code while respecting a set of requirements in term of smoothness of profile, efficiency of (potential) importance sampling and (for axial WRS) equilibrium. This paper illustrate with examples the implementation of the described methods into xLPR v2.0.

scholarly journals The Effects of Starter Film Thickness, Residual Stresses and Layup on GIc of a 0°/0° Interface

1996 ◽  
Vol 5 (6) ◽  
pp. 096369359600500 ◽  
Author(s):  
P. Robinson ◽  
S Foster ◽  
JM Hodgkinson
Keyword(s):  
Fracture Toughness ◽  
Residual Stresses ◽  
Film Thickness ◽  
Mode I ◽  
Epoxy System ◽  
Natural Interface ◽  
Delamination Fracture ◽  
Mode I Delamination

This paper reports on an investigation of the mode I delamination fracture toughness of 0°/0° interfaces in a carbon-epoxy system (T800-924). It has been found that thicker starter films give a lower GIc. The toughness of a natural interface (ie unaffected by the presence of a starter film) has been found to be closest to the toughness measured using the thinnest starter films. Tests on 0°/0° interfaces in multidirectional laminates have shown that residual stresses have a significant effect on GIc. Finally, it has been shown that bend-twist coupling in the arms of the Mode I specimen can lead to considerable changes in the apparent toughness.

CrN/AlN nanolaminates: Architecture, residual stresses, and cracking behavior

2022 ◽  
Vol 40 (1) ◽  
pp. 013414
Author(s):  
K. Bobzin ◽  
T. Brögelmann ◽  
N. C. Kruppe ◽  
H. J. Maier ◽  
T. Heidenblut ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Cracking Behavior

scholarly journals Brittle-to-ductile transition in ultrathin Ta/Cu film systems

2009 ◽  
Vol 24 (6) ◽  
pp. 1906-1918 ◽  
Author(s):  
Patric A. Gruber ◽  
Eduard Arzt ◽  
Ralph Spolenak
Keyword(s):  
Integrated Circuits ◽  
Film Thickness ◽  
Tensile Tests ◽  
Testing Technique ◽  
Cracking Behavior ◽  
Cu Films ◽  
Brittle To Ductile Transition ◽  
Compliant Substrates ◽  
Cu Film

Current semiconductor technology demands the use of compliant substrates for flexible integrated circuits. However, the maximum total strain of such devices is often limited by the extensibility of the metallic components. Although cracking in thin films is extensively studied theoretically, little experimental work has been carried out thus far. Here, we present a systematic study of the cracking behavior of 34- to 506-nm-thick Cu films on polyamide with 3.5-to 19-nm-thick Ta interlayers. The film systems have been investigated by a synchrotron-based tensile testing technique and in situ tensile tests in a scanning electron microscope. By relating the energy release during cracking obtained from the stress-strain curves to the crack area, the fracture toughness of the Cu films can be obtained. It increases with Cu film thickness and decreases with increasing Ta film thickness. Films thinner than 70 nm exhibit brittle fracture, indicating an increasing inherent brittleness of the Cu films.

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