Numerical modeling of microstructural evolution in three-phase polycrystalline materials

Most engineering alloys are used in polycrystalline form. This means that they are made of a large number of grains. The structure formed by the grains is not steady but evolves with time. Understanding the material's microstructure and its evolution helps to control the performance and lifetime of engineering materials. The simulation method based on the Monte Carlo–Potts model of microstructural evolution in a two-phase system has been extended to study microstructural evolution in a three-phase system. The model has been developed and characterized in this study. The model is verified by comparing simulation results of grain growth in the three-phase system to the simulation results in a two-phase system. It is found that grain growth is controlled by diffusion along grain boundaries and follows the power-growth relationship, d~ t 1/n with 1/n= ¼

Grain Size Distribution and topological correlations During Ostwald Ripening: Monte Carlo Potts model simulation

Practically most polycrystalline materials such as ceramics are sintered by liquid during processing; for example, tungsten carbide applied for cutting tools. In liquid sintering, grain structure is controlled by Ostwald ripening. In this work, the Monte Carlo Potts model is employed to simulate Ostwald ripening in solid-liquid mixture. Based on the computer simulation

Solar cell with multilayer structure based on

In this study, a four-layer waveguide structure has been investigated as a solar cell model. In the proposed structure, a nanoparticle composite layer is added to enhance the efficiency of the solar cell due to their ability of controlling the light transmission and reflection. The nanoparticles are taken to be a mixture of Ag and Au embedded in a dielectric media consists of polyacrylic acid laid above a SiNx antireflection coating layer. Both layers are sandwiched between glass substrate and air cladding. The average reflectance for TE and TM fields are calculated using Maple. Results show that the reflectance depends on the ratio of the nanoparticle in the dielectric media, refractive index of SiNx layer and the angle of incidence. Thus, the performance of solar cell has been optimized by tuning and adjusting the above-mentioned parameters

Numerical simulations of coarsening of lamellar structures: applications to metallic alloys

Understanding the microstructural evolution in metallic alloys helps to control their properties and improve their performance in industrial applications. The emphasis of our study is the coarsening mechanisms of lamellar structures

Monte Carlo Implementation for Simulation of Ostwald Ripening Via Long Range Diffusion in Two-Phase Solids

Numerical simulations based on the Monte Carlo Potts model are used to study coupling of grain growth and Ostwald ripening in two-phase polycrystalline materials. The ratio of the grain boundary energy to the interphase boundary energy is used as an input parameter. It is shown that the grain growth in two-phase polycrystalline materials is controlled by long-range diffusion and the change of the mean grain size with time obeys the growth law, n= 0 n+ kt where n is the grain growth exponent. The value of n is calculated for a broad series of volume fractions. It is found that the inverse grain growth exponent, 1/n, in agreement with the theoretical value, 1/n= 1/3, noticed during computer simulations for volume fractions between 40% and 90%. However, the value of 1/n is smaller than 1/3 for volume fractions between 10% and 30%. Furthermore, the temporal development of the number of grains has been analyzed for the entire range of volume fractions. It is also seen that the quasi-stationary state is advanced at varied aging times depending on the volume fractions. Furthermore, it is shown that the simulated size distribution are symmetric and peaked at x= 1 for volume fractions differ between 50% and 90%; however, the simulated size distribution become asymmetric and skew to smaller grains for lower volume fractions change between 10% and 40%