Grain boundary migration and deformation mechanism influenced by heterogeneous precipitate

Understanding the interaction between heterogeneous precipitates and grain boundaries (GBs) is of great significance for tailoring the stability and mechanical properties of nanograined materials. In this work, the nanoscale interaction between the cylindrical precipitate and the migrating GB is investigated by atomic simulation. The results show that the resistance for GB migration can be increased by decreasing the direction angle $$\alpha$$ α (the angle between the axis of the precipitate and the tilt axis of GB). For the larger precipitate, the influence of direction angle is more pronounced. With the increase in shear strain, the interaction between the specific precipitate and GB changes the material deformation mechanism from “GB migration” to “GB migration accompanied with activated dislocations or GB deformation,” which contributes to the softening of the material. By simultaneously tuning the direction angle and size of heterogeneous precipitates, the GB deformation can be strongly inhibited and the stability of GBs can be significantly improved.

A Comparison between ∑3 Asymmetrical Tilt Grain Boundary Energies in Niobium Obtained Analytically and through Molecular Dynamics Based Simulations

Niobium is an important constituent of Zr-Nb alloys being used widely in the nuclear industries as fuel claddings and pressure tubes. In this article, MD based simulations are performed to obtain grain boundary (GB) energies in ∑3 symmetrical and asymmetrical tilt grain boundaries (ATGBs) along <110> tilt axis. Grain boundary energies are also obtained analytically by utilizing the equation establishing the relationship between inclination angle and grain boundary energy for ATGBs. It is observed that in both the cases the GB energies increase with the increase in inclination angle of the ATGBs. The increase in the GB energy follows the same trend with a little offset between the results obtained analytically and MD based simulations. The offset between both the results can be attributed to the limitations of the potentials employed for the simulations. MD based simulations thus provide an accurate method to calculate the GB energies.

Prototype System of Solar Tracking Design to Optimize the Energy Absorption Based on Arduino

This research optimizes the absorption of solar energy in solar panels by designing mechanical systems that can move solar panels in the direction of incoming sunlight. Light-sensitive sensors are used to track the sun. The solar tracking system is designed using two axes, namely rotation axis and the tilt axis. Both axes are driven by servo motors based on light-sensitive sensors. The system was developed using an ATmega328 microcontroller unit. The test results found that using solar tracking the amount of energy produced was greater than static solar panels. Radiation generated between solar tracking and static sun can increase by 55.2%.

Effect of Crack on the Tensile Strength of a Bicrystal Zr - A MD Based Evaluation

In this article, molecular dynamics simulations have been performed to study the effect of crack on the tensile strength of a bicrystal of Zr. Bicrystal with a symmetric tilt grain boundary, with crack and without crack, are generated along [0001] tilt axis. This is further subjected to tensile loading and the stress strain response of the bicrystals with and without crack is studied. The strength of the bicrystal with crack is lower than the one without crack.

Demonstration of the Google Earth as a Tool in Learning the Earth Physics

Earth Physics is a course at the Physics Education Program Study, University of Riau, Indonesia. The problem facing by students were the student commonly not able to imagine the rotation effect and the tilt of rotation axis to some phenomenon. Furthermore the students were difficult to imagine the subduction zone of two tectonic plates. This study was demonstrate some assignments to the student regarding the use Google Earth in the learning the earth physically. In this study, a total of 38 students were chosen to use the Google Earth as an interactive learning media. To demonstrate the Google Earth in the learning process, several assignments have been given to the students. The first was to compare the distance measurement manually and through Google Earth. The second demonstration was to define some selected areas. The third was to demonstrate the tilt axis of rotation effect on the earth. The last was a mini project to demonstrate the use of Google Earth in imagine of the subduction of two tectonic plates. The result shows that mostly students (92%) were able to reconstruction the process involved in the assignment although a few of them cannot explain well. Whilst, 8% of the student were still difficult to reconstruction the process involved in the assignment, although they can submit all the assignments with fairly well. Finally, the Google Earth is generally success used in the demonstration of earth physics subject learning media.

Scanning of two-dimensional space groups

Tables of the scanning of two-dimensional space groups are presented to determine the frieze-group symmetry of lines that transect two-dimensional crystals. It is shown how these tables can be used to predict the (001) projection symmetries of migration-related segments of coincidence site lattice tilt boundaries with [001] tilt axis.