High Temperature Materials Simulations on Parallel Computers
Abstract
Final Progress (1 May 99 - 30 Apr 03): This project deals with properties and processes in high-temperature materials (HTMs) that are vital to the DoD technology base. In this project, molecular-dynamics (MD) simulations have been performed to investigate: i) sintering of nanostructured SiC and high-pressure structural transformation in SiC; ii) dynamic fracture in nanostructured systems; iii) structure of amorphous Al2O3; and iv) reactive wetting of Al2O3 surface by Al. Our joint MD/neutron-scattering study of nanostructured SiC exhibits the onset of sintering at temperature 1,500 K, which is much lower than the bulk sintering temperature. We have proposed a new transition path for the zinc-blende-to-rocksalt transformation of SiC at high pressures. This new mechanism involves no bond breakage and is characterized by a much lower activation barrier compared with previously proposed mechanisms. MD simulations of nanostructured amorphous silica (n-SiO2) reveal that the crack propagates through interfacial regions between silican nanoparticles. A reliable interatomic potential model has been developed for MD simulations of Al2O3. Simulation results for amorphous Al2O3 show predominantly tetrahedral coordination of Al atoms, which agrees with recent experimental results. Our MD simulations on reactive wetting reveal that oxygen atoms from the substrate diffuse into the droplet to form a continuous layer of reaction product at the interface.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 30, 2003
- Accession Number
- ADA420385
Entities
People
- Aiichiro Nakano
- Priya Vashishta
- Rajiv K. Kalia
Organizations
- Louisiana State University