The Effect of Residual Stresses on the Rupture Properties of Film/Substrate Samples

1989 ◽  
Vol 153 ◽  
Author(s):  
M. Ignat ◽  
A. Chouaf ◽  
C. Bernard ◽  
J.M. Terriez
Keyword(s):  
Residual Stresses ◽  
Interfacial Adhesion ◽  
Experimental Results ◽  
Film Substrate ◽  
Rupture Properties

AbstractThe residual stresses of two different film/substrate systems were calculated. Besides, several micromechanical tests were performed. Joining the calculated residual stresses to the analysis of the experimental results, some insight on the interfacial adhesion of film/substrate systems is presented.

Interfacial adhesion of nanoporous zeolite thin films

2006 ◽  
Vol 21 (2) ◽  
pp. 505-511 ◽  
Author(s):  
Lili Hu ◽  
Junlan Wang ◽  
Zijian Li ◽  
Shuang Li ◽  
Yushan Yan
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Interfacial Adhesion ◽  
Interfacial Strength ◽  
Future Generation ◽  
In Situ Growth ◽  
Seeded Growth ◽  
Si Substrates ◽  
Film Substrate

Nanoporous silica zeolite thin films are promising candidates for future generation low-dielectric constant (low-k) materials. During the integration with metal interconnects, residual stresses resulting from the packaging processes may cause the low-k thin films to fracture or delaminate from the substrates. To achieve high-quality low-k zeolite thin films, it is important to carefully evaluate their adhesion performance. In this paper, a previously reported laser spallation technique is modified to investigate the interfacial adhesion of zeolite thin film-Si substrate interfaces fabricated using three different methods: spin-on, seeded growth, and in situ growth. The experimental results reported here show that seeded growth generates films with the highest measured adhesion strength (801 ± 68 MPa), followed by the in situ growth (324 ± 17 MPa), then by the spin-on (111 ± 29 MPa). The influence of the deposition method on film–substrate adhesion is discussed. This is the first time that the interfacial strength of zeolite thin films-Si substrates has been quantitatively evaluated. This paper is of great significance for the future applications of low-k zeolite thin film materials.

The depth distribution of residual stresses in (Ti,Al)N films: Measurement and analysis

2007 ◽  
Vol 22 (10) ◽  
pp. 2659-2662 ◽  
Author(s):  
Sheng-Sheng Zhao ◽  
Hao Du ◽  
Wei-Gang Hua ◽  
Jun Gong ◽  
Jia-Bao Li ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Optical System ◽  
Depth Distribution ◽  
Middle Region ◽  
Chemical Corrosion ◽  
Maximum Value ◽  
Measurement And Analysis ◽  
Film Substrate

A method is introduced to determine the depth distribution of the residual stresses in (Ti,Al)N films. The films were gradually stripped by chemical corrosion, an optical system was designed to test the curvature change of the specimens, and the depth distribution of the residual stresses was calculated. The results show that the residual stresses increase gradually from the interface of film/substrate and reach a maximum value at the middle region, then decrease until the surface.

Finite Element Modeling for Prediction of Residual Stresses in Fiber Reinforced Metal Matrix Composites

1993 ◽  
Author(s):  
Partha Rangaswamy ◽  
N. Jayaraman
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Matrix Material ◽  
Unit Cell ◽  
Experimental Results ◽  
Matrix Composites ◽  
Layer Removal

Abstract In metal matrix composites residual stresses developing during the cool-down process after consolidation due to mismatch in thermal expansion coefficients between the ceramic fibers and metal matrix have been predicted using finite element analysis. Conventionally, unit cell models consisting of a quarter fiber surrounded by the matrix material have been developed for analyzing this problem. Such models have successfully predicted the stresses at the fiber-matrix interface. However, experimental work to measure residual stresses have always been on surfaces far away from the interface region. In this paper, models based on the conventional unit cell (one quarter fiber), one fiber, two fibers have been analyzed. In addition, using the element birth/death options available in the FEM code, the surface layer removal process that is conventionally used in the residual stress measuring technique has been simulated in the model. Such layer removal technique allows us to determine the average surface residual stress after each layer is removed and a direct comparison with experimental results are therefore possible. The predictions are compared with experimental results of an eight-ply unidirectional composite with Ti-24Al-11 Nb as matrix material reinforced with SCS-6 fibers.

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.

An Analysis of the Ultimate Strength of Deck Structures Under In-Plane Loads

1983 ◽  
Vol 20 (03) ◽  
pp. 230-251
Author(s):  
Ygal Shapir ◽  
Gregory J. White
Keyword(s):  
Residual Stresses ◽  
Ultimate Strength ◽  
Experimental Results ◽  
Correction Factors ◽  
Buckling Strength ◽  
Step Procedure ◽  
Simple Program ◽  
Mode Of Failure ◽  
Compressive Loads ◽  
Simple Flow

A step-by-step procedure for determining the mode of failure and the ultimate strength of ship deck structures under in-plane compressive loads is developed. A comparison of several analytical theories for the buckling strength of deck structures in the elastic and inelastic zones is presented and the reason for the approach taken at each step is explained. The final result is a simple flow chart for this procedure and an algorithm which is easily adapted to most computer systems. The procedure is compared with experimental results and a method for determining reasonable size factors of safety (or correction factors) to account for initial deflections, residual stresses, etc., is presented. An example coding in FORTRAN IV for use as a subroutine in larger programs, or as a simple program itself, is given. An example structure is solved to explain each of the steps of the procedure.

scholarly journals A Semianalytical Model for the Determination of Bistability and Curvature of Metallic Cylindrical Shells

2019 ◽  
Vol 3 (1) ◽  
pp. 22
Author(s):  
Pavlo Pavliuchenko ◽  
Marco Teller ◽  
Markus Grüber ◽  
Gerhard Hirt
Keyword(s):  
Residual Stresses ◽  
Shell Thickness ◽  
Cylindrical Shells ◽  
Model Verification ◽  
Experimental Results ◽  
Steel Shell ◽  
Diffraction Measurement ◽  
Stable States ◽  
Forming Process ◽  
Specific Distribution

Bistable metal shells with a fully closed unfolded geometry are of great interest as lightweight construction parts which could be transported without housing and unfolded at the construction place. In order to achieve the effect of bistability in metallic shells, residual stresses with a specific distribution along the shell thickness are necessary. These residual stresses can be introduced in bending processes. The tools with specific bending radii are used to influence the curvature of the shell in the different stable states and thus determine whether a completely closed profile can be achieved. In addition to the forming process, the shell thickness and the shell material have an effect on the achievable geometries and stability. In order to manufacture bistable metallic cylindrical shells from different materials and shell thicknesses, it is necessary to be able to determine a promising process sequence and corresponding bending radii in advance. For this reason, this article presents a semianalytical model for the calculation of bistability and final curvatures. This model is applied to an incremental die-bending process using two bending operations with bending radii of 6 to 12 mm and a 0.2 mm thick steel shell of grade 1.1274 (AISI 1095). The calculation results show that bistability cannot be reached for all combinations of the two bending radii. Moreover, the model indicates that a bistable and fully closed shell is only achieved for a bending radii combination of R1 = 6 mm and R2 = 6 mm. With the aim of model verification, experiments with a closed-die incremental bending tool were performed. Calculated and experimental results show good correlation regarding bistability and curvature. In addition, X-ray diffraction measurement of the residual stresses shows a good qualitative agreement regarding the calculated and experimental results.

A Further Study of Residual Stresses in Circumferential Welds

1973 ◽  
Vol 95 (4) ◽  
pp. 238-242 ◽  
Author(s):  
S. Vaidyanathan ◽  
H. Weiss ◽  
I. Finnie
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Base Metal ◽  
Filler Metal ◽  
Residual Stress Distribution ◽  
Experimental Results ◽  
Circumferential Welds ◽  
Single Pass ◽  
Full Penetration

The residual stress distribution for a circumferential weld between cylinders was obtained in a prior publication for a full penetration, single pass weld with no variation of alloy content across the weld. In the present work the approach is extended to cover a wider variety of weld conditions. It is shown that the effects of multipass welds, partial penetration welds, and welds with filler metal differing greatly in properties from the base metal can approximately be taken into account. Experimental results are presented to support the proposed method of analysis.

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