The Effects of Drive-In Process Parameters on the Residual Stress Profile of the Boron-Doped Silicon Layer

2002 ◽  
Author(s):  
Ok Chan Jeong ◽  
Sang Sik Yang
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Process Parameters ◽  
Boron Concentration ◽  
Silicon Film ◽  
Correlation Coefficients ◽  
Stress Profile ◽  
Residual Tensile Stress ◽  
Residual Stress Profile ◽  
Stress Profiles

The paper represents the effects of the drive-in process parameters on the residual stress profile of the p+ silicon film quantitatively. Since the residual stress profile is not uniform along the direction normal to the surface, the residual stress is assumed to be a polynomial function of the depth. All of the coefficients of the polynomial are determined from the deflections of cantilevers and the displacement of a rotating beam structure, which are measured with a surface profiler meter and a microscope. As the drive-in temperature or the drive-in time increases, the boron concentration decreases and the magnitude of the average residual tensile stress decreases. Also, near the surface of the p+ film the residual tensile stress is transformed into the residual compressive stress and its magnitude increases. The correlation coefficients between the residual stress profiles and the simulated boron concentration are calculated. As the drive-in time and temperature increase, all correlation coefficients become close to 1, and the boron concentration profiles after the drive-in process are similar to the stress profiles. Also, the lattice contractions of test wafers are measured by HRXRD (High Resolution X-Ray Diffractometry).

An Empirical Formula for the Estimation of the Residual Stress in Boron-Doped Silicon Films

2003 ◽  
Author(s):  
Ok Chan Jeong ◽  
Sang Sik Yang
Keyword(s):  
Residual Stress ◽  
Correlation Coefficient ◽  
Concentration Profile ◽  
Empirical Formula ◽  
Boron Concentration ◽  
Silicon Film ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Boron Doped ◽  
Doped Silicon

In this paper, a novel empirical formula is proposed to estimate the residual stress profile as a function of the boron-doped silicon film depth. The residual stress profile is derived from the proposed boron concentration profile, which is a second order function of the film depth, the boron diffusion length, and the correlation coefficient between the residual stress and the boron concentration. The proposed empirical formula is verified by the comparison of the previous results such as the residual stress profiles determined by the quantitative analysis method and the boron concentration profile measured by SIMS and spreading resistance. If the correlation coefficient increases, the residual average and maximum stresses are exponentially reduced. If the drive-in process time or the temperature increase, the compressive stress develops on the surface of the boron-doped silicon film due to the thermal oxidation process.

scholarly journals Parametric Study of Fixtured Vibropeening

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 910 ◽  
Author(s):  
Chan ◽  
Ahluwalia ◽  
Gopinath
Keyword(s):  
Residual Stress ◽  
Process Parameters ◽  
Continuous Treatment ◽  
Optimal Time ◽  
Process Time ◽  
Time Range ◽  
Work Piece ◽  
Stress Profile ◽  
Process Step ◽  
Residual Stress Profile

Vibropeening is a surface treatment process, which combines the peening effect of introducing residual stress with the polishing effect of reducing surface roughness in one single process step. Vibropeening equipment induces vibrations into the media to impart residual compressive stresses in sub-surface layers, as well as polishing on the surface of the work piece. In addition to process parameters, such as vibration frequency, amplitude, and media mass, which are well known in literature, this paper will focus on the study of two additional parameters: immersion depth and process time. It was found that the lower-middle section of the vibratory trough produced the highest Almen deflection. Different continuous treatment times were also studied to explore the maximum introducible residual compressive stress state, and it was concluded that an optimal time range is required to achieve the best residual stress profile. The study demonstrates that different process parameters can influence the effectiveness of the vibropeening process, and that these can be potentially optimized for higher treatment capability.

The Mechanics Basis of Residual Stress Profiles in Proposed API 579 Appendix E

2006 ◽  
Author(s):  
P. Dong ◽  
Z. Cao
Keyword(s):  
Residual Stress ◽  
Heat Input ◽  
Stress Measurement ◽  
Measurement Data ◽  
Stress Profile ◽  
Continuous Change ◽  
Parametric Function ◽  
Residual Stress Profile ◽  
Stress Profiles ◽  
Pipe Geometry

In this paper, the mechanics basis underlying the parametric through-thickness residual stress profiles proposed for the revised API 579 Appendix E are presented. The proposed residual stress profiles are governed to a large extent by a unified parametric function form valid for a broad spectrum of pipe and vessel welds. The functional relationship is established based on the comprehensive knowledge base developed within a recent major international joint industry project (JIP) under the auspice of Pressure Vessel Research Council (PVRC) and a large amount of residuals stress measurement data from recent literature. One of the most important features associated with the proposed revision is that residual stress profile is uniquely determined by two important sets of governing parameters: (1) parameters relevant to pipe geometry, i.e., r/t and t; (2) a parameter related to welding linear heat input Q (J/mm), referred to as the characteristic heat input Qˆ which has a dimension of J/mm3. As a result, the corresponding through-wall residual stress distribution exhibits a continuous change as a function of r/t, t, and Qˆ, instead of falling into a few discrete and unrelated profiles, as seen in the current Codes and Standards.

A New Finite Element Approach Without Chip Formation to Predict Residual Stress Profile Patterns in Metal Cutting

2009 ◽  
Author(s):  
S. Anurag ◽  
Y. B. Guo ◽  
Z. Q. Liu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Hard Turning ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Stress Prediction ◽  
Element Approach ◽  
Stress Profiles

Residual stress prediction in hard turning has been recognized as one of the most important and challenging tasks. A hybrid finite element predictive model has been developed with the concept of plowed depth to predict residual stress profiles in hard turning. With the thermo-mechanical work material properties, residual stress has been predicted by simulating the dynamic turning process followed by a quasi-static stress relaxation process. The residual stress profiles were predicted for a series of plowed depths potentially encountered in machining. The predicted residual stress profiles agree with the experimental one in general. A transition of residual stress profile has been recovered at the critical plowed depth. In addition, the effects of cutting speed, friction coefficient and inelastic heat coefficient on residual stress profiles have also been studied and explained.

Detailed Analysis of Residual Stress Profile at Micro-Scale in Transmission Laser Bonded Titanium/Polyimide System

2008 ◽  
Author(s):  
Ankitkumar P. Dhorajiya ◽  
Mohammed S. Mayeed ◽  
Gregory W. Auner ◽  
Ronald J. Baird ◽  
Golam M. Newaz ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Laser Beam ◽  
Stress Analysis ◽  
Detailed Analysis ◽  
Stress Profile ◽  
Fe Model ◽  
Residual Stress Profile ◽  
Stress Profiles ◽  
Residual Stress Analysis

Detailed analysis of residual stress profile due to laser micro-joining of two dissimilar biocompatible materials, polyimide (PI) and titanium (Ti), is vital for the long-term application of bio-implants. In this work, a comprehensive three dimensional (3D) transient model for sequentially coupled thermo-mechanical analysis of transmission laser micro-joining of two dissimilar materials has been developed by using the finite element (FE) code ABAQUS, along with a moving Gaussian laser heat source. The laser beam (wavelength of 1100 nm and diameter of 0.2 mm), moving at an optimized velocity, passes through the transparent PI, gets absorbed by the absorbing Ti, and eventually melts the PI to form the bond. The laser bonded joint area is 6.5 mm long by 0.3 mm wide. First the transient heat transfer analysis is performed and the nodal temperature profile has been achieved, and then used as an input for the residual stress analysis. Non-uniform mixed meshes have been used and optimized to formulate the 3D FE model and ensure very refined meshing around the bond area. Heat resistance between the two materials has been modeled by using the thermal surface interaction technique, and melting and solidification issues have been approximated in the residual stress analysis by using the appropriate material properties at corresponding temperature. First the model has been used to observe a good bonding condition with the laser parameters like laser traveling speed, power, and beam diameter (burnout temperature of PI > maximum temperature of PI achieved during heating > melting temperature of PI) and a good combination has been found to be 100 mm/min, 3.14 W and 0.2 mm respectively. Using this combination of parameters in heating, the residual stress profile of the laser-micro-joint has been calculated using FE model after cooling the system down to room temperature of 27 °C and analyzed in detail by plotting the stress profiles on the Ti and PI surfaces. Typically the residual stress profiles on the PI surface show low value in the middle, increase to higher values at about 160 μm from the centerline of the laser travel symmetrically at both sides, and to the contrary, on Ti surface show higher values near the centerline of traveling laser beam. The residual stresses have slowly dropped away on both the surfaces as the distance from the bond region increased further. Maximum residual stresses on both the Ti and PI surfaces are at the end of the laser travel, and are in the orders of the yield stresses of respective materials.

Further Research Into Wheel Rim Axial Residual Stress and Vertical Split Rim Failures

2012 ◽  
Author(s):  
Cameron Lonsdale ◽  
John Oliver
Keyword(s):  
Residual Stress ◽  
Tensile Stress ◽  
Stress Profile ◽  
Residual Tensile Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wheel Rim ◽  
Axial Tensile ◽  
Axial Residual Stress ◽  
Class C

Recent work using x-ray diffraction techniques has shown that the axial residual stress pattern within the railroad wheel rim is significantly different for as-manufactured AAR Class C wheels vs. AAR Class C wheels that have failed due to a vertical split rim (VSR), and non-failed AAR Class C wheels that have been operating in service. VSRs almost always begin at areas of tread damage, resulting from shelling or spalling, and cracking propagates into the rim section under load. At the locations tested, the as-manufactured wheels have a relatively “flat” axial residual stress profile, compressive but near neutral, caused by the rim quenching operation, while wheels that have been in service have a layer of high axial compressive stress at the tread surface, and a balancing zone of axial tensile stress underneath. The magnitude and direction of this tensile stress is consistent with the crack propagation of a VSR failure. When cracks from the tread surface propagate into this sub-surface axial tensile zone, a VSR can occur under sufficient additional service loading, such as loads caused by in-service wheel/rail impacts from tread damage. Further, softer Class U wheels, removed from service and tested, were found to have a balancing axial tensile stress layer that is deeper below the tread surface than that found in used Class C wheels. This paper describes further efforts to characterize the axial residual stress present in failed VSR and used Class C wheels. Axial residual stress results are obtained near the initiation point of several VSR wheels using x-ray diffraction. Sub-surface axial residual stress patterns are also determined at points of high out-of-roundness for a group of wheels that were tested for TIR (total indicated runout) on the tread surface. Residual stress data and a photo are presented for a wheel rim slice containing a second VSR crack. Additionally, wheel rim ultrasonic testing data, collected by the wheel manufacturer when the wheels were new, are discussed for wheels that have failed due to VSRs and these data are compared to ultrasonic data for non-VSR wheels. Chemistry data are also compared. These data show that the driving force for VSRs is axial residual tensile stress, not a material cleanliness issue.

Through-Thickness Welding Residual Stress Profile in Dissimilar Metal Nozzle Butt Weld

2010 ◽  
Author(s):  
Tae-Kwang Song ◽  
Ji-Soo Kim ◽  
Chang-Young Oh ◽  
Hong-Yeol Bae ◽  
Jun-Young Jeon ◽  
...  
Keyword(s):  
Residual Stress ◽  
Welding Residual Stress ◽  
Stress Profile ◽  
Pressurized Water ◽  
Butt Weld ◽  
Butt Welds ◽  
Residual Stress Profile ◽  
Dissimilar Metal ◽  
Stress Profiles ◽  
Water Reactors

This paper provides the through-thickness welding residual stress profile in dissimilar metal nozzle butt welds of pressurized water reactors. For systematic investigations of the effects of geometric variables, i.e. the thickness and the radius of the nozzle and the length of the safe end, on welding residual stresses, idealized shape of nozzle is proposed and elastic-plastic thermo-mechanical finite element analyses are conducted. Through-wall welding residual stress profiles for dissimilar metal nozzle butt welds are proposed, which take a modified form of existing welding residual stress profiles developed for austenitic pipe butt weld in R6 code.

Effect of Varying Cold-Drawing Deformation on Residual Stresses Measured by Neutron Diffraction in Steel Rods

2008 ◽  
Vol 571-572 ◽  
pp. 51-56 ◽  
Author(s):  
Jesus Ruiz-Hervias ◽  
Vladimir Luzin ◽  
Henry Prask ◽  
T. Gnaeupel-Herold ◽  
Manuel Elices Calafat
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
True Strain ◽  
Cold Drawing ◽  
Pearlitic Steel ◽  
Stress Profile ◽  
Degree Of Deformation ◽  
Residual Stress Profile ◽  
Stress Profiles ◽  
Tyre Industry

Cold-drawing is employed to fabricate wires and rods, which are mainly used as structural reinforcements in construction as well as in the tyre industry. As a consequence of processing, a residual stress profile is developed. In this paper, residual stress profiles are measured by neutron diffraction in cold-drawn pearlitic steel rods subjected to different deformations (true strain from 0.3 to 1.7). The results show that the residual stress profile produced by cold-drawing is similar in all the samples, irrespective of the degree of deformation.

Assessment of Residual Stress Profiles for Fitness for Service Assessment of Pipe Girth Welds

2014 ◽  
Author(s):  
Pingsha Dong ◽  
Shaopin Song ◽  
Jinmiao Zhang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Solution Procedure ◽  
Stress Profile ◽  
Full Field ◽  
Residual Stress Profile ◽  
Estimation Scheme ◽  
Detailed Assessment ◽  
Stress Profiles ◽  
Girth Welds

This paper aims to provide a detailed assessment of some of the existing residual stress profiles prescribed in widely used fitness-for-service assessment codes and standards, such as BS 7910 Appendix Q, by taking advantage of some comprehensive residual studies that become available recently. After presenting a case study on which residual stress measurements are available for validating finite element based residual stress solution procedure, residual stress profiles stipulated in BS 7910 for girth welds are evaluated in the context of a series of parametric finite element results and a shell theory based full-field residual stress estimation scheme. As a result, a number of areas for improvement in residual stress profile development are identified, including some specific considerations on how to attain some of these improvements.

Residual Stress Profiles of Pipe Girth Weld Using a Stress Decomposition Method

2014 ◽  
Author(s):  
Huaguo Teng ◽  
Steve Bate
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Heuristic Method ◽  
Measurement Data ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Stress Components ◽  
Stress Profiles ◽  
Girth Welds

The application of procedures such as R6 or BS7910 for the structural assessment of defects in pressurised components containing residual stresses requires knowledge of the through-wall residual stress profile. Currently there is much interest in improving the residual stress profiles that are provided in the procedures. In this paper we present an improved analysis of residual stresses of the pipe girth welds by applying the developed heuristic method to one set of extended residual stress measurement data. The through-thickness residual stress is decomposed into three stress components: membrane, bending and self-equilibrating. The heuristic method was applied to the three components separately, so that the residual stress profile was a combination of the three stress components. This form provides not only a clear physical basis for the residual stress profile, but is also convenient for defect assessment where only the membrane and bending stress components are important.

Sign in / Sign up

Export Citation Format

Share Document