Mastering the biaxial stress state in nanometric thin films on flexible substrates

2014 ◽  
Vol 306 ◽  
pp. 70-74 ◽  
Author(s):  
D. Faurie ◽  
P.-O. Renault ◽  
E. Le Bourhis ◽  
G. Geandier ◽  
P. Goudeau ◽  
...  
Keyword(s):  
Thin Films ◽  
Stress State ◽  
Biaxial Stress ◽  
Flexible Substrates ◽  
Biaxial Stress State

Diffraction stress analysis of highly planar-faulted, macroscopically elastically anisotropic thin films and application to tensilely loaded nanocrystalline Ni and Ni(W)

2014 ◽  
Vol 47 (1) ◽  
pp. 291-302 ◽  
Author(s):  
Silke Julia Birgit Kurz ◽  
Udo Welzel ◽  
Ewald Bischoff ◽  
Eric Jan Mittemeijer
Keyword(s):  
Thin Films ◽  
Stress State ◽  
Stress Analysis ◽  
Biaxial Stress ◽  
Stress Factors ◽  
Group Method ◽  
Analysis Method ◽  
Biaxial Stress State ◽  
Successful Separation ◽  
Increased Strength

The presence of planar faults complicates the diffraction stress analysis enormously owing to fault-induced displacement, broadening and asymmetry of the Bragg reflections. A dedicated stress-analysis method has been developed for highly planar-faulted, fibre-textured thin films of cubic crystal symmetry, using only specific reflections for diffraction stress analysis. The effect of unjustified use of other reflections has been demonstrated in the course of application of the method to Ni and Ni(W) thin films exhibiting excessive faulting and subjected to (1) a planar, rotationally symmetric stress state and (2) a planar biaxial stress state. In case 1 the crystallite-group method has been used, whereas in case 2 the stress-analysis method based on X-ray stress factors had to be applied. The successful separation of stress- and fault-induced reflection displacements has enabled the investigation of the mechanical behaviour of Ni and Ni(W) thin films byin situstress measurements during tensile loading, thereby exposing pronounced stiffness and increased strength by alloying with W.

Correlation of stress state and nanohardness via heat treatment of nickel-aluminide multilayer thin films

2004 ◽  
Vol 19 (11) ◽  
pp. 3374-3381 ◽  
Author(s):  
Evan A. Sperling ◽  
Peter M. Anderson ◽  
Jennifer L. Hay
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Stress State ◽  
Internal Stress ◽  
Biaxial Stress ◽  
Multilayer Thin Films ◽  
Bilayer Thickness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Biaxial Stress State

Heat treatment of γ-Ni(Al)/γ′-Ni3Al multilayer thin films demonstrates that multilayer hardness correlates with the magnitude of biaxial stress in alternating layers. Films with a columnar grain morphology and (001) texture were fabricated over a range of volume fraction and bilayer thickness via direct current magnetron sputtering onto NaCl (001) substrates at 623 K. The films were removed from substrates, heat-treated at either 673 K or 1073 K in argon, and then mounted for nanoindentation and x-ray diffraction. The biaxial stress state in each phase was furnished from x-ray diffraction measurement of (002) interplanar spacings. The 673 K treatment increases the magnitude of alternating biaxial stress state by 70 to 100% and increases hardness by 25 to 100%, depending on bilayer thickness. In contrast, the 1073 K heat treatment decreases the stress magnitude by 70% and decreases hardness by 50%. The results suggest that the yield strength of these thin films is controlled, in part, by the magnitude of internal stress. Further, thermal treatments are demonstrated to be an effective means to manipulate internal stress.

Characteristics of Residual Stress by Water-Jet Peening

2013 ◽  
Vol 768-769 ◽  
pp. 564-571 ◽  
Author(s):  
Kenji Suzuki ◽  
Takahisa Shobu ◽  
Ayumi Shiro
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Water Jet ◽  
Biaxial Stress ◽  
X Rays ◽  
Lattice Plane ◽  
Scanning Method ◽  
Depth Direction ◽  
Biaxial Stress State ◽  
Specimen Material

The specimen material was austenitic stainless steel, SUS316L. The residual stress was induced by water-jet peening. The residual stress was measured using the 311 diffraction with conventional X-rays. The measured residual stress showed the equi-biaxial stress state. To investigate thermal stability of the residual stress, the specimen was aged thermally at 773 K in air to 1000 h. The residual stress kept the equi-biaxial stress state against the thermal aging. Lattice plane dependency of the residual stress induced by water-jet peening was evaluated using hard synchrotron X-rays. The residual stress measured by the soft lattice plane showed the equi-biaxial stress state, but the residual stress measured by the hard lattice plane did not. In addition, the distributions of the residual stress in the depth direction were measured using a strain scanning method with hard synchrotron X-rays and neutrons.

Plastic behaviour of perforated sheets under biaxial stress state

1997 ◽  
Vol 39 (7) ◽  
pp. 781-793 ◽  
Author(s):  
Seung Chul Baik ◽  
Heung Nam Han ◽  
Sang Heon Lee ◽  
Kyu Hwan Oh ◽  
Dong Nyung Lee
Keyword(s):  
Stress State ◽  
Biaxial Stress ◽  
Plastic Behaviour ◽  
Biaxial Stress State ◽  
Perforated Sheets

Application of a Multiaxial Fatigue Criterion for the Evaluation of Life of Gears of Complex Geometry

2003 ◽  
Author(s):  
Leonardo Borgianni ◽  
Paola Forte ◽  
Luigi Marchi
Keyword(s):  
Fatigue Life ◽  
Stress State ◽  
Life Prediction ◽  
Complex Geometry ◽  
Biaxial Stress ◽  
Fatigue Life Prediction ◽  
Random Loading ◽  
Complex Load ◽  
Biaxial Stress State ◽  
Principal Axes

Gears can show significant biaxial stress state at tooth root fillet, due to the way they are loaded and their particular geometry. This biaxial stress state can show a significant variability in principal axes during meshing. Moreover loads may have non predictable components that can be evaluated with the aid of recorded data from complex spectra. In these conditions, commonly adopted approaches for fatigue evaluation may be unsuitable for a reliable fatigue life prediction. This work is aimed at discussing a computer implementation of a fatigue life prediction method suitable for multiaxial stress states and constant amplitude or random loading. For random loading a counting procedure to extract cycles from complex load histories is discussed. This method, proposed by Vidal et al., is based on the r.m.s. value of a damage indicator over all the planes through the point where the fatigue life calculation is made. Miner’s rule is used for the evaluation of the overall damage. The whole fatigue life of the component is evaluated in terms of the numbers of repetitions of the loading block. FEM data are used to evaluate stresses under load. The implementation was validated using test data found in the technical literature. Examples of applications to gears are finally discussed.

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