Atomic Processes, and Thermal and Mechanical Properties of Nanophase Ceramics via Multimillion Particle Parallel Molecular Dynamics Simulations

9412965这项计算密集的研究将在并行计算机上用数百万粒子分子动力学模拟来研究纳米陶瓷的结构和物理性能之间的关系。通过原位固结纳米团簇制备的纳米相材料具有超细的微观结构，其中大部分原子位于晶界。纳米陶瓷具有优异的力学性能和较低的烧结温度。将使用包括电荷转移、电子极化率、空间斥力和共价相互作用的影响的粒子间势进行数百万粒子模拟。这些原子模拟的目的是确定(1)结构相关性，特别是纳米相陶瓷中缺陷的性质；(2)界面的动力学粗化；(3)原子扩散和其他动力学过程；(4)纳米相陶瓷的热性能；以及(5)纳米结构陶瓷的力学性能，包括裂纹扩展和断裂以及延性机制。计算研究将利用多台并行计算机来确定一类新的陶瓷材料的性能。这项研究将涉及为这些下一代计算机开发新的计算机代码，并进行复杂的计算。使用平行机和大量相互作用的粒子将允许进行逼真的模拟。

9412965 This computationally intensive research will investigate the relationship between structure and physical properties of nanophase ceramics with multimillion particle molecular dynamics simulations on parallel computers. Synthesized by in situ consolidation of nanometer size clusters, nanophase materials possess ultrafine microstructures with a large fraction of atoms residing in grain boundaries. Nanophase ceramics display superior mechanical properties and have much lower sintering temperature. Multimillion particle simulations will be performed with interparticle potentials that include effects of charge transfer, electronic polarizabilities, steric repulsion, and covalent interactions. The purpose of these atomistic simulations will be to determine (1) structural correlations, in particular the nature of defects in nanophase ceramics; (2) kinetic roughening of interfaces; (3) atomic diffusion and other dynamical processes; (4) thermal properties of nanophase ceramics; and (5) mechanical properties including crack propagation and fracture and the mechanism of ductility in nanostructured ceramics. %%% The computational research will utilize a number of parallel computers to determine the properties of a new class of ceramic materials. The research will involve developing new computer codes for these next generation computers and carrying out sophisticated computations. The use of parallel machines and large numbers of interacting particles will allow realistic simulations to be carried out.