Surface relief effect and atomic site correspondence in the grain boundary α precipitation in a β Ti-Cr alloy

1996 ◽  
Vol 34 (3) ◽  
pp. 381-386 ◽  
Author(s):  
T Furuhara
Keyword(s):  
Grain Boundary ◽  
Surface Relief ◽  
Atomic Site ◽  
Relief Effect ◽  
Surface Relief Effect

Simulation of surface relief effect on ALD process

2006 ◽  
Vol 36 (1-2) ◽  
pp. 36-41 ◽  
Author(s):  
I.G. Neizvestny ◽  
N.L. Shwartz ◽  
Z. Sh. Yanovitskaja ◽  
A.V. Zverev
Keyword(s):  
Surface Relief ◽  
Relief Effect ◽  
Surface Relief Effect

Electro-optical switching of liquid crystal diffraction gratings by using surface relief effect in the photopolymer

2007 ◽  
Vol 273 (2) ◽  
pp. 367-369 ◽  
Author(s):  
Kotakonda Pavani ◽  
Izabela Naydenova ◽  
Suzanne Martin ◽  
Jallapuram Raghavendra ◽  
Robert Howard ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Surface Relief ◽  
Optical Switching ◽  
Diffraction Gratings ◽  
Relief Effect ◽  
Surface Relief Effect

scholarly journals Segregation of P and S Impurities to A Σ9 Grain Boundary in Cu

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1362
Author(s):  
Cláudio M. Lousada ◽  
Pavel A. Korzhavyi
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Coordination Number ◽  
High Performance ◽  
Chemical Properties ◽  
Atomic Scale ◽  
Atomic Site ◽  
Segregation Energy ◽  
Physical Chemical ◽  
Symmetric Tilt

The segregation of P and S to grain boundaries (GBs) in fcc Cu has implications in diverse physical-chemical properties of the material and this can be of particular high relevance when the material is employed in high performance applications. Here, we studied the segregation of P and S to the symmetric tilt Σ9 (22¯1¯) [110], 38.9° GB of fcc Cu. This GB is characterized by a variety of segregation sites within and near the GB plane, with considerable differences in both atomic site volume and coordination number and geometry. We found that the segregation energies of P and S vary considerably both with distance from the GB plane and sites within the GB plane. The segregation energy is significantly large at the GB plane but drops to almost zero at a distance of only ≈3.5 Å from this. Additionally, for each impurity there are considerable variations in energy (up to 0.6 eV) between segregation sites in the GB plane. These variations have origins both in differences in coordination number and atomic site volume with the effect of coordination number dominating. For sites with the same coordination number, up to a certain atomic site volume, a larger atomic site volume leads to a stronger segregation. After that limit in volume has been reached, a larger volume leads to weaker segregation. The fact that the segregation energy varies with such magnitude within the Σ9 GB plane may have implications in the accumulation of these impurities at these GBs in the material. Because of this, atomic-scale variations of concentration of P and S are expected to occur at the Σ9 GB center and in other GBs with similar features.

Influence of Slip Localization on Surface Relief Formation and Grain Boundary Microcrack Nucleation

2011 ◽  
Vol 465 ◽  
pp. 35-40 ◽  
Author(s):  
Maxime Sauzay ◽  
Pierre Evrard ◽  
Karine Bavard
Keyword(s):  
Aspect Ratio ◽  
Stress Field ◽  
Grain Boundary ◽  
Slip Band ◽  
Surface Relief ◽  
Tensile Deformation ◽  
Equivalent Stress ◽  
Slip Bands ◽  
Relief Formation ◽  
Analytical Formulae

Slip localization is often observed in metallic polycrystals after cyclic deformation (persistent slip bands) or pre-irradiation followed by tensile deformation (channels). To evaluate its influence on surface relief formation and grain boundary microcrack nucleation, crystalline finite element (FE) computations are carried out using microstructure inputs (slip band aspect ratio/spacing). Slip bands (low critical resolved shear stress (CRSS)) are embedded in small elastic aggregates. Slip band aspect ratio and neighboring grain orientations influence strongly the surface slips. But only a weak effect of slip band CRSS, spacing and grain boundary orientation is observed. Analytical formulae are deduced which allow an easy prediction of the surface and bulk slips. The computed slips are in agreement with experimental measures (AFM/TEM measures on pre-irradiated austenitic stainless steels and nickel, copper and precipitate-strengthened alloy subjected to cyclic loading). Grain boundary normal stresses are computed for various materials and loading conditions. A square root dependence with respect to the distance to the slip band corner is found similarly to the pile-up stress field. But the equivalent stress intensity factor is considerably lower. Analytical formulae are proposed for predicting the grain boundary normal stress field depending on the microstructure lengths. Finally, an energy balance criterion is applied using the equivalent elastic energy release rate and the surface/grain boundary energies. The predicted macroscopic stresses for microcrack nucleation are compared to the experimental ones.

Behavior of Hydrogen in Tensile-Deformed Aluminum Alloys

2018 ◽  
Vol 941 ◽  
pp. 1295-1299 ◽  
Author(s):  
Toshiaki Manaka ◽  
Goroh Itoh
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Hydrogen Evolution ◽  
Surface Relief ◽  
Specimen Surface ◽  
Hydrogen Atoms ◽  
Surface Oxide Film ◽  
Tensile Direction ◽  
Free Zone ◽  
Surface Breakage

Behavior of hydrogen in tensile-deformed Al-9mass%Mg and Al-5.8mass%Zn-2.4mass%Mg alloys was investigated by means of hydrogen microprint technique, HMPT, a method to visualize the microscopic location of hydrogen evolution from specimen surface as silver particles. Both in the two alloys, surface relief was formed at most grain boundaries by the stretching, while hydrogen evolution was observed at some grain boundaries. The evolution of hydrogen was discussed with parameters such as the angle between grain boundary on the specimen surface and tensile direction, the angle between grain boundary on the surface and slip line inside the grain, the height of the surface relief, and maximum gradient of the surface relief. The results indicated that the shear deformation along grain boundary caused transportation of hydrogen atoms with gliding dislocations to the surface, breakage of surface oxide film. In the Al-Zn-Mg alloy, it was suggested that the preferential deformation in the precipitate free zone was attributed to hydrogen evolution.

Atomic site determination of a high-purity SiC grain boundary

2002 ◽  
Vol 82 (5) ◽  
pp. 857-866 ◽  
Author(s):  
E. Takuma ◽  
H. Ichinose
Keyword(s):  
Grain Boundary ◽  
High Purity ◽  
Atomic Site
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