scholarly journals Special Issues/Internal Stresses in Surface Treated Layers. The Internal Stress of Electroless Deposits.

1992 ◽  
Vol 43 (7) ◽  
pp. 656-666 ◽  
Author(s):  
Katsushige IWAMATSU ◽  
Kuniaki OTSUKA ◽  
Kaoru NAITO
Keyword(s):  
Internal Stress ◽  
Internal Stresses

Internal Stresses in Nanocrystalline Nickel and Nickel-Iron Alloys

2012 ◽  
Vol 706-709 ◽  
pp. 1607-1611 ◽  
Author(s):  
J.D. Giallonardo ◽  
Uwe Erb ◽  
G. Palumbo ◽  
G.A. Botton ◽  
C. Andrei
Keyword(s):  
Grain Size ◽  
Internal Stress ◽  
Structural Difference ◽  
Intrinsic Stress ◽  
Internal Stresses ◽  
Second Phase ◽  
Nickel Iron ◽  
Second Phase Particles ◽  
Second Phases ◽  
Rule Out

Nanocrystalline metals are often produced in a state of stress which can adversely affect certain properties, e.g. corrosion resistance, wear, fatigue strength, etc. This stress is referred to as internal or “intrinsic” stress since it is not directly caused by applied loads. The structural causes of these stresses in nanocrystalline materials are not fully understood and are therefore an area of particular interest. The internal stresses of nanocrystalline Ni and Ni-16wt%Fe were measured and found to increase with the addition of iron. Characterization using HR-TEM revealed no signs of porosity, second phase particles, or a high density of dislocations. Both materials possessed well defined high-angle grain boundaries. The main structural difference between the two materials was found to be grain size and correspondingly, a decrease in grain size resulted in an increase in internal stress which supports the applicability of the coalescence theory. The current study also provides evidence to rule out the effect of voids (or porosity), dislocations, and second phases as possible causes of internal stress.

scholarly journals Application of the Mathar Method to Identify Internal Stress Variation in Steel as a Welding Process Result

2017 ◽  
Vol 25 (2) ◽  
pp. 125-136
Author(s):  
Dariusz Kowalski
Keyword(s):  
Internal Stress ◽  
Welding Process ◽  
Internal Stresses ◽  
Induced Voltage ◽  
Stress Variation ◽  
Steel Members ◽  
Electric Arc Welding ◽  
Destructive Measurement ◽  
Non Destructive ◽  
Excessive Stress

Abstract The paper deals with the method to identify internal stresses in two-dimensional steel members. Steel members were investigated in the delivery stage and after assembly, by means of electric-arc welding. In order to perform the member assessment two methods to identify the stress variation were applied. The first is a non-destructive measurement method employing local external magnetic field and to detecting the induced voltage, including Barkhausen noise The analysis of the latter allows to assess internal stresses in a surface layer of the material. The second method, essential in the paper, is a semi-trepanation Mathar method of tensometric strain variation measurement in the course of a controlled void-making in the material. Variation of internal stress distribution in the material led to the choice of welding technology to join. The assembly process altered the actual stresses and made up new stresses, triggering post-welding stresses as a response for the excessive stress variation.

Research on Internal Stress in Electroplated Cu Films and Ni Films on Ag Substrates

2011 ◽  
Vol 287-290 ◽  
pp. 3085-3088
Author(s):  
Yao Min Zhu ◽  
Shan Shan Wang ◽  
Feng Zhang Ren
Keyword(s):  
Film Thickness ◽  
Internal Stress ◽  
Calculation Model ◽  
Internal Stresses ◽  
Film Material ◽  
Beam Test ◽  
Cu Films ◽  
Cu Film ◽  
Reduced Gradient

Electroplating was employed to prepare Cu films and Ni films on Ag substrates. The average internal stresses in Cu film and Ni film were measured in situ by cantilever beam test. The values of experimental internal stresses were compared with theoretical internal stresses. The results showed that the internal stresses of Cu film and Ni film decreased with the increase of the film thickness. The reduced gradient was faster. The values of experimental and theoretical internal stresses had the same variation trend with film thickness and the same characteristics (tensile stress). Theoretical calculation model of internal stress was of accuracy. The internal stress for the same substrate was in relation to the film material.

Comparison of Internal and Residual Stresses Measured by Strain-Dip Test and XRD during High Temperature Deformation of Al-Mg Solid Solutions

2013 ◽  
Vol 768-769 ◽  
pp. 351-357
Author(s):  
H. Sato ◽  
Y. Enomoto ◽  
K. Omote ◽  
S.I. Tanaka
Keyword(s):  
High Temperature ◽  
Residual Stresses ◽  
Internal Stress ◽  
Applied Stress ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Deformation Condition ◽  
Internal Stresses ◽  
Principal Stresses ◽  
Dip Test

Creep behavior of solid solution alloys are reasonably explained by concepts of the “internal and effective stress of high temperature deformation”. The internal stress is considered to be brought by formation of dislocation substructures, and the dislocation structures should have caused long range stress filed in interior of materials. Thus, residual stresses should also be brought by the same origin. In this paper, measurements of the residual stresses after creep deformation by 2D-Xray method are attempt, and the stresses are compared with so-called the “internal stress of high temperature deformation” measured by strain-dip stress-transient test. Although, the stress tensor depends on the deformation condition, the relation with the applied stress show complex manner at a glance. The maximum principal stresses, however, show relatively smaller than the applied stress, and fairly agree with that measured by strain-dip stress-transient technique. Importance of further considerations of the origin of so-called internal stresses is suggested.

Internal Stresses and Adhesion Properties of Film/Substrate Interfaces

1990 ◽  
Vol 188 ◽  
Author(s):  
M. Ignat ◽  
A. Chouaf ◽  
Ph. Normandon
Keyword(s):  
Stress Relaxation ◽  
Internal Stress ◽  
Experimental Methods ◽  
Internal Stresses ◽  
Silicon Substrates ◽  
Stress Evolution ◽  
Adhesion Properties ◽  
External Stresses ◽  
Film Substrate

ABSTRACTThe evolution of internal stresses in Tungsten films deposited on Silicon substrates submitted to external stresses is discussed here. The stresses are estimated and measured by theoretical and experimental methods. The discussion of the internal stress evolution is shown to be dependent of the film/substrate interfaces, and of the loss of adhesion inducing stress relaxation.

Internal Stresses in Elastohydrodynamic Lubrication of Rolling/Sliding Contacts

1989 ◽  
Vol 111 (1) ◽  
pp. 180-187 ◽  
Author(s):  
Farshid Sadeghi ◽  
Ping C. Sui
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Internal Stress ◽  
Maximum Shear Stress ◽  
Elastohydrodynamic Lubrication ◽  
Normal Pressure ◽  
Internal Stresses ◽  
Stress Distributions ◽  
Principal Stresses ◽  
Dimensionless Velocity

The internal stress distribution in elastohydrodynamic lubrication of rolling/sliding line contact was obtained. The technique involves the full EHD solution and the use of Lagrangian quadrature to obtain the internal stress distributions in the x, y, z-directions and the shear stress distribution as a function of the normal pressure and the friction force. The principal stresses and the maximum shear stress were calculated for dimensionless loads ranging from (2.0452 × 10−5) to (1.3 × 10−4) and dimensionless velocity of 10−10 to 10−11 for slip ratios ranging from 0 to pure sliding condition.

Investigation on Internal Stress of SU-8 Photoresist Film

2014 ◽  
Vol 613 ◽  
pp. 251-258 ◽  
Author(s):  
Xiao Lei Zhang ◽  
Li Qun Du ◽  
Shen Miao Zhu
Keyword(s):  
Internal Stress ◽  
Theory Model ◽  
Internal Stresses ◽  
Paper Substrate ◽  
Effect Factor ◽  
Ansys Simulation ◽  
Main Effect ◽  
Photoresist Film ◽  
Substrate Curvature ◽  
Analytical Result

In this paper, substrate curvature method was adopted and a theory model based on Stoneys formula was built for obtaining the internal stress of SU-8 film. The effect of substrate diameter, film thickness and post-baked temperature on substrate curvature ratio was investigated by ANSYS simulation. The analytical result shows that post-baked temperature is the main effect factor on internal stress of SU-8 film. In addition, internal stresses of SU-8 at three different post-temperatures (55°C, 70°C and 85°C) are measured. The results show that the experimental results greatly agreed with simulation analytical results. It means the internal stress of SU-8 film can be accurately described by the theory model, which provides a basis for the quantitative analysis of the internal stress in SU-8 film.

Finite Element Simulation of Steel Quench Distortion- Parametric Analysis of Processing Variables

2012 ◽  
Vol 1485 ◽  
pp. 29-34 ◽  
Author(s):  
F. A. García-Pastor ◽  
R.D. López-García ◽  
E. Alfaro-López ◽  
M. J. Castro-Román
Keyword(s):  
Finite Element ◽  
Martensitic Transformation ◽  
Internal Stress ◽  
Thermal Stresses ◽  
Stress Fields ◽  
Leaf Spring ◽  
Internal Stresses ◽  
Processing Temperature ◽  
Fe Model ◽  
Slow Cooling

ABSTRACTSteel quenching from the austenite region is a widely used industrial process to increase strength and hardness through the martensitic transformation. It is well known, however, that it is very likely that macroscopic distortion occurs during the quenching process. This distortion is caused by the rapidly varying internal stress fields, which may change sign between tension and compression several times during quenching. If the maximum internal stress is greater than the yield stress at given processing temperature, plastic deformation will occur and, depending on its magnitude, macroscopic distortion may become apparent.The complex interaction between thermal contraction and the expansion resulting from the martensitic transformation is behind the sign changes in the internal stress fields. Variations in the steel composition and cooling rate will result in a number of different paths, which the internal stresses will follow during processing. Depending on the route followed, the martensitic transformation may hinder the thermal stresses evolution to the point where the stress fields throughout the component may actually be reverted. A different path may support the thermal stresses evolution further increasing their magnitude. The cross-sectional area also affects the internal stresses magnitude, since smaller areas will have further trouble to accommodate stress, thus increasing the distortion. Additionally, the bainitic transformation occurring during relatively slow cooling rates may have an important effect in the final stress field state.A finite-element (FE) model of steel quenching has been developed in the DEFORM 3D simulation environment. This model has taken into account the kinetics of both austenite-bainite and austenite-martensite transformations in a simplified leaf spring geometry. The results are discussed in terms of the optimal processing parameters obtained by the simulation against the limitations in current industrial practice.

Dip-Test Internal Stress and the Composite Model of Creep Deformation

2005 ◽  
Vol 482 ◽  
pp. 291-294 ◽  
Author(s):  
Ferdinand Dobeš ◽  
Alena Orlová
Keyword(s):  
Internal Stress ◽  
Elevated Temperatures ◽  
Volume Fraction ◽  
Local Density ◽  
Creep Behaviour ◽  
Composite Model ◽  
Internal Stresses ◽  
Present Contribution ◽  
Test Technique ◽  
Dip Test

The composite model of plastic deformation is regarded as a realistic approximation of creep behaviour at elevated temperatures in a well-developed substructure consisting of dislocationdense subgrain boundaries (hard regions) and subgrain interiors (soft regions) with relatively low dislocation density. In the present contribution, the model is applied for an estimation of internal stresses that are experimentally measured by the dip-test technique. Two situations are considered within the model: (i) the density of moving dislocations is the same in both hard and soft regions and (ii) the density of moving dislocations is proportional to the local density in the respective region. The model enables to express the internal stress in terms of microstructural variables found by independent microscopic observations. It is shown that the magnitude of volume fraction of hard and soft region in the composite model has only a small effect on the value of internal stress.

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