scholarly journals In Situ X-ray Diffraction Analysis of Stresses during Deep Rolling of Steel

2018 ◽  
Vol 2 (4) ◽  
pp. 20 ◽  
Author(s):  
Heiner Meyer ◽  
Jérémy Epp
Keyword(s):  
Plastic Deformation ◽  
Synchrotron Radiation ◽  
Residual Stresses ◽  
Contact Point ◽  
Stress Fields ◽  
Deep Rolling ◽  
2D Strain ◽  
Material State ◽  
Material Load

Residual stresses originating from elasto-plastic deformation during mechanical processing can be analyzed post-process with various known methods. A new measurement method to measure and evaluate the strain and stress fields in situ under the contact point during a deep rolling process was developed to describe the dependence of the residual stresses from the internal material load. Using synchrotron radiation at European Synchrotron Radiation Facility (ESRF) (ID11), diffraction measurements were performed in transmission geometry during dynamical loading with different process parameters. The strain and stress fields were analyzed with high spatial resolution in an 8 mm × 4 mm area around the contact point during the process using a 13-mm tungsten carbide roller on samples of AISI 4140H steel. Fast data acquisition allowed the reconstruction of full two-dimensional (2D) strain and stress maps. These could be used to determine the response from the initial material state in front of the roller to the mechanically loaded region with plastic deformation up to the processed material with the resulting residual stresses. This comprehensive analysis was then used to link the internal material load with the resulting residual stresses in the final material state.

scholarly journals Spatial Internal Material Load and Residual Stress Distribution Evolution in Synchrotron In Situ Investigations of Deep Rolling

2020 ◽  
Vol 4 (1) ◽  
pp. 3
Author(s):  
Heiner Meyer ◽  
Jérémy Epp
Keyword(s):  
Residual Stress ◽  
Synchrotron Radiation ◽  
Rolling Process ◽  
European Synchrotron Radiation Facility ◽  
Von Mises Stress ◽  
Deep Rolling ◽  
Static Indentation ◽  
Material Load ◽  
Von Mises

Mechanical loading scenarios, comparable to a deep rolling process, were reproduced in static indentation experiments on AISI 4140H steel samples with a cylindrical deep rolling tool and investigated in situ with synchrotron radiation at the European Synchrotron Radiation Facility (ESRF) on beamline ID11. Through the use of spatially resolved diffraction data, two-dimensional (2D) equivalent von Mises stress maps were recorded during loading and after unloading. The material modifications were analyzed in the material below the contact zone for different loading conditions. It was demonstrated that the characteristics of internal material load and residual stress distributions can be evaluated through data fitting and the effect of the applied force could be linked to the stress fields by an empirical model. The experimental values were then compared to a contact mechanics approach in order to analyze the correlation between the theoretical maximum loading stresses and the stored elastic residual stresses remaining by considering the dissipation of a certain amount of energy through plastic deformation.

The temperature effect on the plastic deformation of the Mg88Zn7Y5 alloy with LPSO phase studied by in-situ synchrotron radiation diffraction

2021 ◽  
Vol 138 ◽  
pp. 107321
Author(s):  
Klaudia Fekete ◽  
Gergely Farkas ◽  
Daria Drozdenko ◽  
Domonkos Tolnai ◽  
Andreas Stark ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Synchrotron Radiation ◽  
Temperature Effect ◽  
Lpso Phase ◽  
Synchrotron Radiation Diffraction

In-situ observation of plastic deformation of Fe-Si bicrystals by white-beam synchrotron radiation topography

1998 ◽  
Vol 78 (1) ◽  
pp. 105-130 ◽  
Author(s):  
M. Polcarova ◽  
J. Gemperlova ◽  
J. Bradler ◽  
A. Jacques ◽  
A. George ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Synchrotron Radiation ◽  
In Situ Observation ◽  
White Beam

Dislocation Density Effect on Thermal Diffusivity of AISI 316 Steel

2014 ◽  
Vol 605 ◽  
pp. 27-30 ◽  
Author(s):  
Girolamo Costanza ◽  
Roberto Montanari ◽  
Stefano Paoloni ◽  
Maria Elisa Tata
Keyword(s):  
Plastic Deformation ◽  
Thermal Diffusivity ◽  
Dislocation Density ◽  
Elastic Stress ◽  
Tensile Tests ◽  
Stress Fields ◽  
Scattering Mechanism ◽  
Dislocations Density ◽  
Aisi 316

AISI 316 steel samples have been investigated by infrared thermography (IRT) after introducing controlled degrees of plastic deformation by means of tensile tests. Microstructural examinations of the same samples showed that the progressive decrease of thermal diffusivity observed for successive steps of plastic deformation is due to the increase of dislocation density. Dislocations affect thermal diffusivity in two ways, by acting as centres of scattering and by inducing elastic stress fields. To evaluate the two contributions, IRT measurements have been also carried outin-situ,during tensile tests at progressively increasing strain. For relevant plastic deformation, the dislocations mainly affect the thermal diffusivity by scattering mechanism. On the basis of these results, it can be concluded that thermal diffusivity is significantly affected by the increase of dislocations density therefore locally resolved IRT measurements seem promising to detect states of local plasticization in mechanical components.

In-situ observation of plastic deformation of Fe-Si bicrystals by white-beam synchrotron radiation topography

1998 ◽  
Vol 78 (1) ◽  
pp. 105-130 ◽  
Author(s):  
M. Polcarová ◽  
J. Gemperlová ◽  
J. Brádler ◽  
A. Jacques ◽  
A. George ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Synchrotron Radiation ◽  
In Situ Observation ◽  
White Beam

Neutron Diffraction and Acoustic Emission Study of Mg-Al-Sr Alloy Reinforced with Short Saffil® Fibers Deformed in Compression

2014 ◽  
Vol 777 ◽  
pp. 92-98 ◽  
Author(s):  
Gergely Farkas ◽  
Kristián Máthis ◽  
Petr Lukáš ◽  
Jan Pilch ◽  
Miroslav Vrána ◽  
...  
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Acoustic Emission ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Deformation Mechanisms ◽  
Ex Situ ◽  
The Matrix ◽  
Main Deformation

Neutron diffraction method has been applied in theex-situinvestigation of the residual stresses in Mg-5wt.%Al-1 wt.%Sr (AJ51) magnesium alloy reinforced with short Saffil® fibers deformed in compression at room temperature. The residual stresses were measured in the axial and radial directions with respect to the load direction. It is shown that in the initial state the tensile stress is present in the matrix phase. Thein-situacoustic emission measurements were performed with the aim to reveal the main deformation mechanisms operating in the particular stages of the plastic deformation. Ex-situ neutron diffractions experiments showed that the tensile axial residual stress in the matrix increases with increasing plastic deformation while the radial residual stress decreases. In situ acoustic emission measurements indicate that the main deformation mechanisms are twinning and glide of bigger dislocation ensembles in the early stages of the compressive deformation while the fibers breakage was observed in the vicinity of the maximum stress.

scholarly journals Thermal Effects on Surface and Subsurface Modifications in Laser-Combined Deep Rolling

2021 ◽  
Vol 5 (2) ◽  
pp. 55
Author(s):  
Robert Zmich ◽  
Daniel Meyer
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Thermal Loads ◽  
Deep Rolling ◽  
Mechanical Loads ◽  
Thermomechanical Process ◽  
Compressive Stresses ◽  
New Process ◽  
Negative Effect ◽  
Compressive Residual Stresses

Knowledge of the relationships between thermomechanical process loads and the resulting modifications in the surface layer enables targeted adjustments of the required surface integrity independent of the manufacturing process. In various processes with thermomechanical impact, thermal and mechanical loads act simultaneously and affect each other. Thus, the effects on the modifications are interdependent. To gain a better understanding of the interactions of the two loads, it is necessary to vary thermal and mechanical loads independently. A new process of laser-combined deep rolling can fulfil exactly this requirement. The presented findings demonstrate that thermal loads can support the generation of residual compressive stresses to a certain extent. If the thermal loads are increased further, this has a negative effect on the surface layer and the residual stresses are shifted in the direction of tension. The results show the optimum range of thermal loads to further increase the compressive residual stresses in the surface layer and allow to gain a better understanding of the interactions between thermal and mechanical loads.

scholarly journals A new development of four-point method to measure the electrical resistivity in situ during plastic deformation

Measurement ◽  
2021 ◽  
pp. 109547
Author(s):  
Saeid Saberi ◽  
Martin Stockinger ◽  
Christian Stoeckl ◽  
Bruno Buchmayr ◽  
Helmut Weiss ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Electrical Resistivity ◽  
Point Method ◽  
New Development
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