Molecular-dynamics study of compressive stress generation

1996 ◽  
Vol 53 (7) ◽  
pp. 4117-4124 ◽  
Author(s):  
N. A. Marks ◽  
D. R. McKenzie ◽  
B. A. Pailthorpe
Keyword(s):  
Molecular Dynamics ◽  
Compressive Stress ◽  
Stress Generation

scholarly journals Direct observation of pore collapse and tensile stress generation on pore walls due to salt crystallization in a PDMS channel

Soft Matter ◽  
2019 ◽  
Vol 15 (22) ◽  
pp. 4562-4569 ◽  
Author(s):  
Antoine Naillon ◽  
Pierre Joseph ◽  
Marc Prat
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Direct Observation ◽  
Stress Generation ◽  
Salt Crystallization ◽  
Pore Collapse ◽  
Crystallization Pressure ◽  
Salt Crystallisation ◽  
Pdms Channel ◽  
Classical Picture

In contrast with the classical picture where the generation of stress on pore walls due to salt crystallisation is analysed by a compressive stress using the concept of crystallization pressure, we report a mechanism leading to the generation of a local tensile stress.

Real time in-situ stress evolution investigation of highly textured electrodeposited bismuth thin films

2003 ◽  
Vol 781 ◽  
Author(s):  
Donglei Fan ◽  
Frank Q. Zhu ◽  
Ingrid X. Shao ◽  
P. C. Searson ◽  
R. C. Cammarata
Keyword(s):  
Real Time ◽  
Compressive Stress ◽  
Film Growth ◽  
Stress Measurement ◽  
Mean Free Path ◽  
In Situ Stress ◽  
Stress Generation ◽  
In Situ Stress Measurement ◽  
Bismuth Films

AbstractBismuth, a semi-metal with very long mean free path and large magnetoresistance (MR) effect, is a novel candidate material for thin film spintronic devices. Electrochemical deposition followed by a post-deposition anneal has resulted in highly textured bismuth films as characterized by x-ray diffractometry and pole figure measurements. A highly sensitive, real time in-situ stress measurement system was designed and employed to study stress generation during bismuth film growth. Bismuth films displayed a monotonically increasing compressive stress during deposition. The magnitude of the compressive stress decreased with the deposition rate in the range 1.5 Å/sec to 50 Å/sec.

Sensitivity of a Rotating Beam Sensor for Stress Evaluation in Aluminium Thin Films

2005 ◽  
Vol 490-491 ◽  
pp. 649-654 ◽  
Author(s):  
J.M.M. dos Santos ◽  
J.C.P. Pina ◽  
António Castanhola Batista ◽  
Alton B. Horsfall ◽  
Kai Wang ◽  
...  
Keyword(s):  
Compressive Stress ◽  
Incident Angle ◽  
Stress Generation ◽  
Aluminum Layer ◽  
X Ray Diffraction ◽  
Rotating Beam ◽  
X Ray ◽  
Reflected Light ◽  
Sensor Structure ◽  
Stress States

The evaluation of stress in sub-micron tracks is critical for the microelectronics industry and there is a need for new methods of measurement. This paper advocates the use of a rotating beam sensor structure which can be fabricated on the wafer along side electronic devices and used to monitor stress generation and relaxation as a function of processing. The rotation can be observed with a reflected light microscope and correlated to the actual stress level. Several samples, assputtered and sintered, were prepared with the aim of having different residual stress states. X-ray diffraction with a low incident angle geometry, was used to evaluate the residual stresses on the aluminum layer. Computer simulations using ANSYS were also performed in order to correlate the sensor rotation with the experimental stress values. It was observed that the extrinsic stress from the mismatch in expansion coefficients between the aluminum layer and the silicon substrate dominates over the compressive stress from the sputter growth. Sintering the layers at temperatures above 150°C reduces this compressive stress due to the action of creep. The calibration of the rotation of the device with the direct measurements of the X-ray diffraction shows that the sensor has a resolution better than 2.8 MPa.

Local compressive stress generation in electron irradiated boron-doped Si0.75 Ge0.25 /Si devices

2012 ◽  
Vol 9 (10-11) ◽  
pp. 2058-2061 ◽  
Author(s):  
Isao Tsunoda ◽  
Toshiyuki Nakashima ◽  
Nobuyuki Naka ◽  
Tatsuya Idemoto ◽  
Masashi Yoneoka ◽  
...  
Keyword(s):  
Compressive Stress ◽  
Stress Generation ◽  
Boron Doped

Molecular Dynamics Simulation of Shot Peening Process and Residual Stress Generation: Effects of Particle Impact Speed and Impinging Angle

2014 ◽  
Author(s):  
Yachao Wang ◽  
Jing Shi ◽  
Xinnan Wang
Keyword(s):  
Molecular Dynamics ◽  
Residual Stress ◽  
Stress Distribution ◽  
Shot Peening ◽  
Md Simulation ◽  
Stress Generation ◽  
Dynamics Simulation ◽  
Surface Finishing ◽  
In Situ Observation ◽  
The Impact

Shot peening is a well-known surface finishing process that is often applied to enhance the residual stress distribution in the component surfaces. In this study, we carry out a molecular dynamics (MD) simulation study to investigate the single particle shot peening process on the (100) silicon surface at nano scale. The MD simulation enables in-situ observation and analysis of complex material deformation mechanisms in the presences of ultra-high strain rate, such as stress distribution, dislocation propagation, and particle/workpiece interface interaction. Three levels of shot speed (i.e., 200, 500, and 800 m/s) and three levels of impinging angle (i.e., 30°, 60°, and 90°) are configured in the simulation. It is found that higher shot speeds result in deeper depths of residual indentation, deeper penetration depths of residual stress below surface, and higher magnitude of maximum compressive stress. The residual stress distributions underneath the shot-peened surfaces exhibit strong anisotropic manner. Residual stress only concentrates in the area along the impact direction; and the decrease of impact angle results in shallower penetration of residual stress.

Measurement of Stress Development during HVOF Thermal Spray

1997 ◽  
Author(s):  
S. Kuroda ◽  
Y. Tashiro ◽  
H. Yumoto ◽  
S. Taira ◽  
H. Fukanuma
Keyword(s):  
Compressive Stress ◽  
Substrate Surface ◽  
Stress Generation ◽  
Powder Materials ◽  
Stress Evolution ◽  
Hvof Process ◽  
Hvof Thermal Spray ◽  
Hvof Spray ◽  
Stress Buildup

Abstract Direct and quantitative observation of the stress generation during HVOF spray is carried out by measuring the curvature of substrates in-situ during spraying. A high pressure HVOF gun is used to spray SUS316L, Hastelloy C and WC-12%Co powder onto SUS316L substrates. The observed curvature data indicate that there are 3 regimes of stress evolution during the HVOF spray: (1) generation of compressive stress on the substrate surface at the beginning of spraying, (2) stress buildup in the coating during spraying, and (3) superposition of stress due to the mismatch in the thermal expansivity between the coating and the substrate as the specimen cools down to the room temperature after fabrication. Compressive stress ranging from 70 to 400 MPa is observed in the second regime during the HVOF spray; the value depending on the powder materials and spray conditions. Microstructural observation reveals that a significant portion of the coatings consists of poorly molten particles. Beneath the coatings formed by the HVOF process, a thin layer of increased hardness exists within the substrate.

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